The cognitive treatment components and therapies of cognitive behavioral therapy for insomnia: A systematic review

Sleep Medicine Reviews xxx (2018) 1e18

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Sleep Medicine Reviews journal homepage: www.elsevier.com/locate/smrv

CLINICAL REVIEW

The cognitive treatment components and therapies of cognitive behavioral therapy for insomnia: A systematic review € jmark a, *, Annika Norell-Clarke b Markus Jansson-Fro a b

Centre for Psychiatry Research, Department of Clinical Neuroscience, Karolinska Institute, Stockholm, Sweden Centre for Research on Child and Adolescent Mental Health, Karlstad University, SE-651 88 Karlstad, Sweden

a r t i c l e i n f o

s u m m a r y

Article history: Received 23 November 2017 Received in revised form 5 March 2018 Accepted 1 May 2018 Available online xxx

Since the beginning of the twenty-first century, there has been an increased focus on developing and testing cognitive components and therapies for insomnia disorder. The aim of the current review was thus to describe and review the efficacy of cognitive components and therapies for insomnia. A systematic review was conducted on 32 studies (N ¼ 1455 subjects) identified through database searches. Criteria for inclusion required that each study constituted a report of outcome from a cognitive component or therapy, that the study had a group protocol, adult participants with diagnosed insomnia or undiagnosed insomnia symptoms or reported poor sleep, and that the study was published until and including 2016 in English. Each study was systematically reviewed with a standard coding sheet. Several cognitive components, a multi-component cognitive program, and cognitive therapy were identified. It is concluded that there is support for paradoxical intention and cognitive therapy. There are also other cognitive interventions that appears promising, such as cognitive refocusing and behavioral experiments. For most interventions, the study quality was rated as low to moderate. We conclude that several cognitive treatment components and therapies can be viewed as efficacious or promising interventions for patients with insomnia disorder. Methodologically stronger studies are, however, warranted. © 2018 Elsevier Ltd. All rights reserved.

Keywords: Insomnia Cognitive therapy Efficacy Systematic review CBT

Insomnia disorder is characterized by difficulties in initiating sleep at bedtime, frequent or prolonged awakenings, or earlymorning awakenings with an inability to return to sleep [1,2]. These nocturnal symptoms occur despite adequate opportunity for sleep and are associated with clinically significant distress or impairment of daytime functioning, including fatigue, decreased energy, mood disturbances, and reduced cognitive functions. A diagnosis of insomnia disorder requires sleep difficulties that are present for 3 nights or more per week and lasts for more than 3 months [1,2]. The prevalence rate of insomnia disorder is approximately 10% in the population. Insomnia disorder is commonly associated with medical as well as mental disorders, and evidence clearly shows that insomnia disorder is a risk factor for a host of

Abbreviations: BT-I, behavior therapy for insomnia; CBT-I, cognitive behavior therapy for insomnia; CT-I, cognitive therapy for insomnia; DSM-5, Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition; MeSH, Medical Subject Headings; RCT, randomized controlled trial; SD, standard deviation; UCT, uncontrolled trial. * Corresponding author. Centre for Psychotherapy Education and Research, 117 63 Stockholm, Sweden. € jmark). E-mail address: [email protected] (M. Jansson-Fro

other disorders, such as depression. Insomnia disorder is also associated with significant direct and indirect costs [3]. Cognitive behavioral therapy for insomnia (CBT-I) is a timelimited and structured treatment for patients with insomnia disorder. The therapy usually consists of several elements, with the most common being psychoeducation about sleep, insomnia, and sleep hygiene, components to address dysfunctional sleep behaviors, techniques to reduce unhelpful cognitive processes (e.g., beliefs and expectations), and various forms of relaxation or mindfulness training [4]. Recent meta-analyses and systematic reviews have shown that CBT-I improves insomnia symptomatology, and it is now considered the treatment-of-choice for patients with insomnia disorder [5e7]. Though CBT-I has been demonstrated to have clear efficacy, several conceptual issues remain largely unanswered. One of these issues is the limited evidence for the efficacy of various CBT-I components for insomnia disorder [8,9]. While studies examining the efficacy of CBT-I mainly comprise of behavioral and cognitive strategies in a combined format, very little is known empirically about each of these elements, particularly so for cognitive components [10,11]. While it is beneficial for the evidence-base that

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several behavioral strategies have been explored in a relatively detailed manner and demonstrated to have marked efficacy on their own (e.g., sleep restriction) [12], it is problematic that little effort has been made to develop and validate cognitive interventions. Theoretically, several dominant models of insomnia underscore cognitive processes that are implicated in the maintenance of insomnia [13e16]. In turn, this points to the need to address cognitive processes in therapy with cognitive or behaviorally-oriented interventions [17]. It is also important to point out that some of the cognitive processes in these models are well-researched [18], with evidence supporting the notion that cognitive mechanisms are involved in maintaining insomnia disorder. A second major issue is that although CBT-I is a wellresearched and evidence-based intervention, only a smaller fraction (20e30%) remit from insomnia and a substantial number of patients do not benefit at all [4]. Though it is premature at this point to speculate whether or not cognitive components might increase the number of patients that remit or respond, existing cognitive models suggest the possibility for further refinement and improvement for CBT-I. In areas where cognitive processes have been more heavily scrutinized (e.g., social anxiety disorder), development of new or revising of previous therapies has led to the development of highly effective treatments (e.g., cognitive therapy for social anxiety disorder [19]). The development and validation of cognitive therapeutic interventions thus seems central. Since the end of the 1970's, insomnia-related cognitive components have been developed, validated, and revised. Though there are marked differences between the cognitive interventions in terms of content, these interventions share a common theoretical underpinning, namely that a change in cognitive processes is necessary to impact insomnia symptomology; not only alterations in homeostatic and circadian systems [9]. Early cognitive components, developed during the 70's and 80's, that were investigated in smaller trials, were paradoxical intention, imagery training, and distraction. Since the beginning of the twenty-first century, there has been increased focus on developing and testing cognitive components for insomnia. The latter work has included the development and exploration of interventions that target worry, problem-solving, emotional processing, coping with perceived threats, and sleep misperception. Lately, cognitive therapy, uniquely adapted to insomnia disorder, has been described and examined [20]. In 2006, it was concluded in a review that there was insufficient evidence for cognitive restructuring - probably the most commonly used cognitive component in CBT-I manuals - as a treatment intervention for insomnia disorder [21]. Since 2006, the research field has grown substantially. Yet there has been no scientific attempt to examine the literature so far, thus we believe that it is time to review what is known empirically concerning the cognitive components of CBT-I. The aim of the current systematic review was therefore to assess the efficacy of cognitive components and cognitive therapies for insomnia disorder. Methods A systematic review approach was used. A meta-analysis was not considered appropriate due to the small number of studies available for each cognitive component or therapy and the substantial heterogeneity in the methodology and outcomes of included studies. The review was pre-registered at PROSPERO in June 2017 (https://www.crd.york.ac.uk/PROSPERO/#index.php). Search strategy An extensive database search was conducted in December 2016 by two project-independent librarians at Karolinska Institute

University Library in order to find all studies that evaluated the efficacy of a cognitive component or a cognitive therapy for insomnia. The search was carried out by using six online bibliographic databases [i.e., Medline (Ovid), Psycinfo (Ovid), Embase (Elsevier), Cochrane (Wiley), Cinahl (Ebsco), and Dissertations and Theses (ProQuest)]. The search strategies were developed by two librarians in collaboration with the first author. The strategies were based on several MeSH and keyword search terms. Across the databases, terms were used to identify studies in which patients with insomnia had been included and a cognitive component or therapy had been employed (e.g., paradoxical intention, imagery, problem solving, and constructive worry). For a complete description of the search strategies, see the Supplemental Material (Table S1). Further, the first author reviewed the reference lists of recent reviews and meta-analyses of the efficacy of CBT-I. Finally, the reference list of each study included in the present review was examined. Selection procedure As is displayed in Fig. 1, the database search yielded a total of 4063 records from the six databases, out of which 1609 titles were duplicates. One additional record was identified via the reference list from an included study. Thus, 2455 records were the focus for further review. These records were screened via a systematic review web app (https://rayyan.qcri.org). The abstracts of all the titles were initially screened by the first author to exclude irrelevant studies. Only peer-reviewed published articles were retained. The inclusion criteria for the studies in the present review were: 1) the study was a randomized controlled trial, uncontrolled group trial, or experimental group study, 2) the study constituted a report of treatment outcome using at least one outcome assessing insomnia symptomatology (i.e., nighttime and daytime symptoms); 3) a psychological treatment with a cognitive component/therapy was tested on at least one group and the component/therapy was theoretically intended to reverse cognitive processes (e.g., expectations, beliefs, attributions, and performance anxiety) [10]; 4) the participants were adults; 5) the participants had been diagnosed with insomnia (i.e., primary, secondary or comorbid), had undiagnosed problems initiating or maintaining sleep, or reported poor sleep; 6) the study was published before or during December 2016; and 7) the study was published in English. Concerning the population-criterion (e), we included studies in which participants were described as having insomnia symptoms or poor sleep (i.e. not fulfilling all criteria for insomnia disorder) due to the growing evidence for and trend in diagnostic systems towards a dimensional view of psychopathology [22,23]. As mindfulness approaches have recently been examined in reviews [24e26], studies exploring the efficacy of mindfulness-based stress reduction or mindfulnessbased cognitive therapy were excluded from this review. In total, 2380 records were excluded based on the criteria described above. Full-texts of the remaining 75 references were evaluated by the first author. The second author was consulted in cases of uncertainty concerning inclusion. The two authors discussed disagreements until a negotiated conclusion was reached. At this stage, the criteria described above for inclusion and exclusion were used. In total, 32 records were included at this stage (the excluded 43 studies with reasons for exclusion are displayed in Table S2). Data extraction The 32 records were then reviewed by two pairs of independent raters. All four raters were students in their tenth and final term at the Master of Science in Clinical Psychology program, and the raters were paid for their work. Before rating the included studies, all

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Records idenfied through database searches (n = 4063)

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Addional records idenfied through other sources (n = 1)

Records aer duplicates removed (n = 2455)

Records screened (n = 2455)

Records excluded (n = 2380)

Full-text arcles assessed for eligibility (n = 75)

Full-text arcles excluded, with reasons: Not a group study, same sample or sample overlap, no relevant outcomes, only abstract or trial protocol, intervenon not cognive, not individuals with sleep difficules (n = 43)

Studies included in review (n = 32)

Fig. 1. PRISMA study inclusion flowchart.

raters were given detailed instructions in a booklet. They were also asked to rate two project-independent studies (i.e., two papers investigating the efficacy of CBT for anxiety and depressive disorders), which was followed by feedback on the ratings by the first author and the other rater in the pair. Each rater used a standard extraction sheet to summarize information about the study: study design, sample size, diagnosis [i.e., insomnia disorder/primary insomnia, insomnia symptoms (not fulfilling all criteria for a diagnosis), or poor sleep (no evidence of insomnia symptoms)], mean age, % women, % study attrition, type of cognitive components or therapies and control conditions, treatment delivery (i.e., dosage and format), outcome measures (i.e., insomnia-related nighttime and daytime symptoms as well as cognitive processes), and findings. Data extraction was completed independently and discrepancies between the two raters in the pairs were resolved through discussion with the first author.

study report free of suggestion of selective outcome reporting (e.g., results for all included outcomes are described) [10], intervention components clearly described (including treatment content and dosage), and [11] a study population with verified sleep problems, e.g., based on DSM-5 criteria for insomnia disorder [2]. Scores were “0” (No), “1” (Partly/unclear), and “2” (Yes), yielding a total quality score range of 0e22. To increase the validity of the quality scores, the quality ratings were conducted independently by the two authors. Disagreements and uncertainties were discussed among the authors until a negotiated final score was reached for each study. Since one included study had been authored by the first author [30], the quality assessment was carried out by the two authors and a project- and study-independent researcher. Following this, the total score differed by one point; the lower score, scored by the two authors, was chosen as the final score for this study. Results

Assessment of study quality Study characteristics Quality assessments of the included studies were indexed. As in a previous review on insomnia disorder [27], eight modified items from the Jadad scale [28] together with one item from the Cochrane assessment of bias tool [29], and two insomnia-related study quality criteria were used. In total, each study was assessed in terms of their quality based on eleven items [1]: randomization procedure clearly described [2], allocation concealed for researchers during the intervention [3], clear description of non-responders, withdrawals, and dropouts, with CONSORT flow chart [4], study objectives clearly defined [5], outcome measures clearly defined [6], inclusion and exclusion criteria clearly described [7], sample size justified (e.g., power calculation) [8], statistical methods clearly described, including missing values, intention-to-treat etc. [9],

After the screening process, 32 papers were included in the current review, including a total of 1455 patients. The investigations differed in their design: 29 were RCTs or experimental studies and three were UCTs. The included participants' age and gender varied across studies, but a great majority of the participants were women (82.7% of participants) and either young adults (55.5%) or middle-aged adults (37.0%) (calculations based on studies in which data was available). The definitions of sleep problems differed across studies: 22 included patients with insomnia disorder (or primary insomnia), eight included those with insomnia symptoms [defined so due to no assessment of distress or functional impairment [2]], and two studies included participants

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Table 1 Description of the cognitive components and therapies for insomnia. Component or therapy

Description

Behavioral experiments

Behavioral experiments are carefully planned activities, which the patient conducts, with the purpose of testing an unhelpful belief and formulating more adaptive beliefs based on the experiment's outcome (73). See Cognitive therapy, Reducing clock monitoring and Reducing sleep misperception for insomnia treatment contexts. The cognitive program consists of a combination of techniques aimed at affecting maintaining cognitive factors [49]. The cognitive program includes Cognitive restructuring, Paradoxical intention, Thought stopping and a form of Coping imagery (more detailed descriptions of every technique are available under specific headings in the table). Cognitive refocusing is based on cognitive models that delineate arousing thought content as a maintaining factor in insomnia [59]. Cognitive refocusing aims to reduce arousing thought content by instructing patients to choose engaging yet non-arousing thought topics to focus on, such as the plot in a film or by focusing on external stimuli such as an audiobook [35]. By doing so, it is proposed that this shift in attention will improve sleep. Patients are instructed to apply cognitive refocusing at bedtime and if they wake up during the night. See similarities to Distraction and Imagery training. The use of cognitive restructuring in insomnia is based on models that suggest that dysfunctional beliefs about sleep have a maintaining role in insomnia (e.g. [15]). Cognitive restructuring commonly means teaching patients to identify individual dysfunctional beliefs, observe the effect beliefs have on mood, and to restructure beliefs by questioning them and formulating alternative beliefs that are more realistic. Cognitive therapy for insomnia is based on a cognitive model of insomnia [15,19]. Cognitive therapy aims to reverse a broader range of cognitive maintaining mechanisms, namely (a) unhelpful beliefs about sleep, (b) sleep-related or sleep-interfering worry and rumination, (c) attentional bias and monitoring for sleep-related threat, (d) misperception of sleep and daytime deficits, and (e) the use of safety behaviors that maintain unhelpful beliefs. Cognitive therapy aims to reverse these cognitive maintaining mechanisms during the daytime and the nighttime through the identification of maladaptive beliefs and strategies, and individually formulated Behavioral experiments to test beliefs and alter habits. Constructive worry (also labeled ‘worry control’ in the literature) is based on research showing that many patients with insomnia are prone to pre-sleep worry and also believe that worry serves a purpose [34]. In constructive worry, the patients are instructed to deliberately engage in worry outside the bed, early in the evening, and to use problem-solving regarding their concerns. Thus, worry is moved from the sleep-onset period and the bed, and takes on a more constructive form. Together this is meant to decrease pre-sleep arousal and thereby decrease involuntarily awake time in bed. Coping imagery consists of four techniques aimed to alter patients' pre-sleep arousing cognitions [36]. For example, patients are instructed to imagine emotionally salient situations (both sleep-related and non sleep-related) and to alter the situations mentally in ways what will give a stronger sense of control (e.g. mentally writing down intrusive thoughts and then erasing them, or mentally putting one's evening worries in a worry box which will be examined in the morning). For other techniques, patients are instructed to mentally alter upsetting situations by pairing them with something positive (e.g. imagine that one has super powers and therefore is well equipped to deal with daytime tasks after a night's poor sleep). The purpose with distraction is to disrupt cognitive activities that interferes with sleep by introducing stimuli that will be engaging yet not arousing for the patients while in bed. Examples of distracting stimuli includes imagining an interesting and engaging situation [62]. See similarities to Cognitive refocusing and Imagery training. Imagery training is aimed at controlling pre-sleep cognitive arousal by focusing attention on neutral stimuli. Pictures of six neutral objects are shown to patients and they are taught how to visualize the objects independently [46]. Patients are instructed to use the visualizations whenever they are unable to fall asleep. See similarities to Cognitive refocusing and Distraction. The ambition to decrease verbal thoughts and increase visual imagery comes from the literature on worry, which suggests that although thinking (worrying) in images is associated with increased somatic arousal and more distress in short-term, it can also lead to increased emotional processing which in turn would decrease worry and distress (74). As people with insomnia often are prone to worry in bed, and worry is associated with sleep problems [15], advice could be given on how to worry more productively. So far, this technique has only been used experimentally regarding insomnia [37]. Paradoxical intention is based on the notion that people with insomnia exacerbate their condition by attempting to control the sleep process (75). In paradoxical intention, the patient is instructed to attempt to remain awake (as long as possible) rather than trying to fall asleep. In the original instructions, the patient is asked to lie in bed in a darkened room, keeping his or her eyes open (as long as possible). The patient is also instructed not to engage in sleep-incompatible behavior (e.g., reading or watching TV). Instructions and rationales for patients have varied in different paradigms, e.g. that trying to stay awake decreases performance anxiety (Type A rationale) vs trying to stay awake works as a desensitization of anxiety-provoking thoughts (Type B rationale). Rationales commonly resembles one of the two abovementioned rationales but exceptions should be noted (e.g. 41). The use of the Pennebaker writing intervention for insomnia is based on research that demonstrates that patients with insomnia engage in worry and perceive it as a major impediment to sleep [15] and on research that shows that people with insomnia have a tendency to internalize emotions; thereby suggesting incomplete emotional processing of daily events and hassles [15]. In the Pennebaker writing intervention, patients are instructed to write their deepest thoughts or emotions down in detail before bedtime. It is believed that the Pennebaker writing intervention will reduce worry, which, in turn, will promote sleep onset. The use of problem solving therapy is based on research that shows that excessive worry is maintaining insomnia [53]. By improving problem solving skills, it is believed that worry (and sleep difficulties) will be reduced. In problem solving, the patient is provided education about the importance of effective problem-solving, types of problem-solving, instructions in rational problem-solving techniques, and enhancement of problem orientation. The patient may choose to focus on his or her current sleep problem or another distressing or disruptive problem. See similarities with Constructive worry. Reduced clock monitoring is based on research demonstrating that paying attention to the time during the night increases worry and contributes to difficulties falling asleep [57]. Clients may be simply advised to avoid looking at the clock while lying in bed, as part of a cognitive refocusing treatment [50] but clock monitoring may also be specifically challenged through a Behavioral experiment, where clients experimentally test (for example) whether clock monitoring vs not monitoring the clock is associated with better sleep. The ambition to reduce sleep misperception is based on research that demonstrates that people with insomnia subjectively overestimate their sleep problems, which leads to increased worry and exacerbates insomnia according to the cognitive model of insomnia [15]. Sleep misperception is countered by demonstrating objective sleep data (e.g. from actigraphy) to patients, which in turn is proposed to decrease worry and thereby improve sleep. Ideally, this is demonstrated through a Behavioral experiment where patients themselves are taught how to contrast subjective and objective sleep measures from a specific night's sleep rather than just being informed of the results [56]. The use of thought stopping in insomnia is based on the theory that sleep onset latency will decrease if negative sleep-related thoughts at bedtime will be stopped or decreased [45]. Thought stopping is first practiced with a therapist who intervenes by yelling “stop” after being given a que that patients are thinking negative thoughts. When patients are confident that they can stop their thoughts independently, they are instructed to practice the technique at daytime and especially at bedtime.

Cognitive program

Cognitive refocusing

Cognitive restructuring

Cognitive therapy

Constructive worry

Coping imagery

Distraction

Imagery training

Increased visual imagery

Paradoxical intention

Pennebaker writing intervention

Problem solving therapy

Reducing clock monitoring

Reducing sleep misperception

Thought stopping

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with “poor sleep” (based on cutoffs from generic insomnia symptoms questionnaires). Though the majority of studies administered treatment in an individual format, interventions in six studies were delivered in a group or self-help format. On average, 3.4 sessions (SD ¼ 2.8, range: 1e22 sessions) were devoted to administering the cognitive components or therapies [two studies excluded in the calculation due to missing data [31,32]]. Sleep diaries were a common method for assessing outcomes (k ¼ 30 studies), and selfreport instruments or questions were also prevalent (k ¼ 25 studies). The use of objective sleep recordings was less common (k ¼ 7 studies). For more details, see Table 2. Concerning control conditions, both passive and active control conditions were used. Nineteen RCTs compared a cognitive component or therapy with a more passive comparator, i.e., psychoeducation, monitoring, no treatment or a waitlist control [31e49]. Four RCTs used a psychological placebo as a comparator [33,34,36,47,50]. One RCT compared a cognitive program with biofeedback [51]. Eight RCTs used one or several behavioral therapy component as a comparator, e.g., stimulus control or relaxation [30,31,42,44,45,47,49,52]. Four RCTs compared a cognitive component or therapy with another cognitive component, mindfulnessbased intervention, behavior therapy, or cognitive behavior therapy [39,53e55]. Finally, six studies can be categorized as experimental tests that used a behavioral experiment in which the comparator consisted of instructing the participants to test an alternate behavior or receiving differing feedback [40,41,56e58]. Concerning quality assessments of the included studies, the two raters agreed on 324 (92.2%) of the 352 individual study quality ratings. Disagreements were discussed in depth between the two authors and a final rating was negotiated (Supplemental Material: Table S3). The mean final total quality rating was 13.1 (SD ¼ 2.7; range: 8e21; maximum: 22). The two most common methodological limitations were that the group allocation was not sufficiently concealed to researchers, and that the studies' sample sizes had not been based on statistical power calculations. Description of cognitive components and therapies for insomnia This review identified empirical tests of cognitive components and cognitive therapies in the research literature. A description of the components and therapies is available in Table 1. Evidence for cognitive components and therapies for insomnia In the following section, we review the evidence for the cognitive components and therapies for insomnia. A description of the included studies is available in Table 2. Cognitive program One study has investigated a combination of cognitive techniques vs biofeedback, with the ambition to test the matching of patients with treatments [51]. The cognitive program consisted of cognitive restructuring, paradoxical intention, thought stopping and form of coping imagery. Patients were assigned to treatments based on their pre-sleep cognitive arousal: half of those with high arousal were randomized to the cognitive program and the other half to biofeedback, and likewise for those with low arousal. The cognitive program resulted in significantly greater reduction on pre-sleep arousal at post-treatment: those with high pre-sleep cognitive arousal benefitted more. Both therapies reduced sleep onset latency, increased total sleep time and increased sleep quality at post-treatment. Counter-intuitively, biofeedback was more beneficial for sleep quality for those with high pre-sleep cognitive intrusions whereas those with low pre-sleep cognitive intrusions benefitted more from the cognitive program, which raises some

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questions regarding the active mechanisms in the two treatments. The results were maintained at follow-ups, at which point there were no significant differences between the four groups. Cognitive refocusing Three studies investigated the efficacy of cognitive refocusing in participants with primary insomnia or insomnia symptoms [38,52,59]. The first investigation was a three-armed RCT comparing the efficacy of one session of cognitive refocusing (administered as an audiobook) or cognitive refocusing (relaxation training) with self-monitoring [38]. All three groups had improved on subjective sleep parameters and on two cognitive-affective measures (anxiety and self-efficacy) at post-treatment. There were no significant improvements on daytime or additional cognitive-affective measures. The results were similar at the 2week follow-up. The second study used an uncontrolled trial design with ten patients [59]. The investigation showed that four sessions of cognitive refocusing increased sleep quality at posttreatment and follow-up and reduced insomnia severity at follow-up. Cognitive refocusing did not have a significant impact on sleep diary parameters or arousing sleep content. The third investigation was a RCT comparing the efficacy of one session of cognitive refocusing plus sleep hygiene with sleep hygiene only [52]. The findings indicated that cognitive refocusing plus sleep hygiene was superior to sleep hygiene in reducing insomnia severity at posttreatment. Also, cognitive refocusing plus sleep hygiene resulted in more treatment responders, relative to sleep hygiene only. However, cognitive refocusing did not lead to superior improvements on somatic or cognitive pre-sleep arousal. Cognitive restructuring One study examined cognitive restructuring and problem solving as techniques for those with insomnia disorder [54]. Cognitive restructuring plus behavior therapy (i.e., stimulus control, sleep hygiene, and progressive relaxation) was compared with problem solving plus behavior therapy. All patients received behavior therapy during one small-group session and were randomized to either problem solving or cognitive restructuring; both administered individually across five sessions. The findings indicate that both groups had similar outcomes at post-treatment and follow-up. Both groups improved on sleep onset latency, times waking up, wake after sleep onset, total sleep time, sleep efficiency, insomnia severity, sleep quality, number of responders and remitters, problem-solving skills and orientations, unhelpful beliefs about sleep, and worry. The only difference between the two groups was that those receiving cognitive restructuring had a faster reduction on unhelpful beliefs about sleep, relative to those who received problem solving. This study suggests that cognitive restructuring might be equally effective as problem solving and tentatively that both interventions might have efficacy in their own right. Cognitive therapy Three studies have investigated the efficacy of cognitive therapy for insomnia (CT-I) [20,53,55] (see Table 1 for treatment content). The first investigation was an uncontrolled study in which nineteen patients with insomnia were administered CT-I [20]. Due to comorbidity and heterogeneity in the therapists' experience with the protocol, the number of sessions varied from 6 to 22 across the patients (mean: 14 sessions). The findings showed that CT-I, at posttreatment and follow-ups, reduced insomnia severity, sleep onset latency, wake after sleep onset, unhelpful beliefs about sleep, sleeprelated worry, cognitive arousal, attention and monitoring for sleeprelated threat, safety behaviors, depression, and anxiety. Also, CT-I had a positive impact on total sleep time. Finally, none of the patients met criteria for insomnia at post-treatment and follow-ups. In

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Design

Sample: Size, diagnosis, age (M), % female, % attrition

Treatment type

Treatment delivery

Outcomes

Findings

Quality score

Cognitive program Sanavio, 1988 [51]

RCT

24, psychophysiological insomnia, 39 y, 58%, NR

(a) Cognitive program e high pre-sleep cognitive activation (PSCA) (b) Cognitive program e low PCSA (c) Biofeedback e high PCSA (d) Biofeedback e low PCSA

(a - d) 6 sessions, individual format

Sleep diary (SOL, NAW, TST, tension, SQ), PICI

Cognitive program had a greater reduction on pre-sleep intrusions at post-treatment. Those with high PSCA benefitted more on pre-sleep intrusions from therapies at post-treatment. All therapies reduced SOL, increased TST, and increased sleep quality at posttreatment. Biofeedback meant a greater reduction on tension at post-treatment. Those with high PSCA benefitted more from biofeedback on SQ, and those with low PSCA more from the cognitive program. Maintained results at 3- and 12-month follow-ups.

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Cognitive refocusing Creti, 1998 [38]

RCT

52, sleep-onset and/or -maintenance insomnia, 67 y, 68%, 21%

(a) Cognitive refocusing (audiobook) (b) Cognitive refocusing (relaxation) (c) Self-monitoring / randomized to (a) or (b)

(a e b) 1 session, individual format

Sleep diary (SOL, WASO, TST, SE, SQ, fatigue, daytime function, morning restedness, mental activity, physical tension), insomnia frequency, distress frequency, SES, SSS, PSAS, ASSQ

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Gellis et al., 2013 [52]

RCT

62, insomnia symptoms, NR, 65%, 19%

(a) Cognitive refocusing þ Sleep hygiene (b) Sleep hygiene

(a e b) 1 session, individual format

ISI, PSAS-S, PSAS-C

Gellis, 2012 [59]

UCT

10, primary insomnia, 49 y, 10%, 0%

(a) Cognitive refocusing

(a) 4 sessions, individual format

Sleep diary (SOL, WASO, NAW, TST, SE), PSQI, ISI, arousing sleep content

All three groups improved on sleepwake and subjective sleep parameters (SOL, WASO, TST, SE, SQ, and insomnia frequency) and on two cognitiveaffective measures (ASSQ and SES) at post-treatment. No significant improvement on daytime or additional cognitive-affective measures. No significant differences in improvement between the three groups. Similar findings at 2-weeks follow-up. Cognitive refocusing þ Sleep hygiene demonstrated larger reduction on ISI and more responders at post-treatment than sleep hygiene only. No follow-up. Cognitive refocusing resulted in reduction on PSQI at post-treatment and follow-up and reduction on ISI at 1month follow-up.

Cognitive restructuring Pech & O'Kearney, 2013 [54]

RCT

47, insomnia disorder, 34 e45 y, 62%, 15%

(a) Behavior therapy þ Cognitive restructuring (b) Behavior therapy þ Problem solving

(a e b) 1 session BT, group format (a e b) 5 sessions of PS or CRES, individual format

Sleep diary (SOL, NAW, WASO, TST, SE, medication or alcohol), ISI, PSQI, SPSIR:S, DBAS, PSWQ

Following full treatment, both groups improved on SOL, NAW, WASO, TST, SE, medication or alcohol, ISI, PSQI, number of responders and remitters, SPSI-R:S, DBAS, and PSWQ at post-treatment and 1-month follow-up. Behavior therapy þ Cognitive restructuring displayed faster reduction on DBAS.

17

UCT

19, primary insomnia, 49 y, 53%, 0%

(a) Cognitive therapy

(a) 6e22 sessions (mean 14 sessions), individual format

Sleep diary (SOL, WASO, TST), ISI, WSAS, DBAS, APSQ, PSAS-C, SAMI, SRBQ, BDI, BAI, diagnosis

Cognitive therapy reduced ISI, SOL, WASO, DBAS, APSQ, PSAS-C, SAMI, SRBQ, BDI and BAI, and increased TST, at post-treatment and 3-, 6-, and 12month follow-ups. 0% met criteria for insomnia at post-treatment and followups.

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Cognitive therapy Harvey et al., 2007 [20]

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€ jmark M, Norell-Clarke A, The cognitive treatment components and therapies of cognitive Please cite this article in press as: Jansson-Fro behavioral therapy for insomnia: A systematic review, Sleep Medicine Reviews (2018), https://doi.org/10.1016/j.smrv.2018.05.001

Table 2 Description of studies examining cognitive components or therapies for insomnia: Design, sample description, treatment type, treatment delivery, outcomes, findings, and quality score.

RCT

188, insomnia disorder, 47 y, 62%, 11%

(a) Cognitive therapy (b) Behavior therapy (c) Cognitive behavior therapy

(a e c) 8 sessions (CT and BT: 45 e60 min; CBT: 75 min), individual format

Sleep diary (SOL, WASO, TST, SE), ISI, polysomnography (SOL, WASO, TST, SE), MFI, WSAS, SF-36

Wong et al., 2015 [55]

RCT

64, insomnia disorder, 49 y, 63%, 11%

(a) Behavior therapy during first phase; randomized into (b), (c), (d) or (e) during second phase (b) Cognitive therapy immediately (c) Mindfulness-based therapy immediately (d) Cognitive therapy after 4 weeks (e) Mindfulness-based therapy after 4 weeks

(a) 4 sessions, individual format (b - c) 4 sessions, individual format

ISI, PSQI, sleep diary (TST), actigraphy (TST), DASS

Constructive worry €jmark et al., Jansson-Fro 2012 [30]

RCT

22, insomnia disorder, 56 y, 52%, 9%

(a) Behavior therapy (b) Behavior therapy þ Constructive worry

(a þ b) 4 sessions, individual format

Sleep diary (TWT, TST), ISI, APSQ, WSAS

All therapies reduced ISI at posttreatment; cognitive behavior therapy was more effective in decreasing ISI than cognitive therapy. There were more treatment responders in cognitive behavior therapy and behavior therapy at post-treatment and an increase in treatment responders at 6-month follow-up in cognitive therapy and decrease in behavior therapy. A higher rate of remission was noted in cognitive behavior therapy than in cognitive therapy at post-treatment but not at follow-up. There was an increase in remission rate in cognitive therapy from post-treatment to follow-up. A larger reduction was demonstrated in behavior therapy, relative to cognitive therapy, on SOL and WASO. All therapies increased TST. Cognitive behavior therapy and behavior therapy displayed larger reduction on SE at post-treatment. Polysomnography post-treatment: cognitive behavior therapy and behavior therapy displayed larger reduction on SOL and larger increase on SE, behavior therapy larger reduction on WASO. All therapies reduced WSAS and mental health problems (SF-36). First phase: Behavior therapy resulted in improvements on ISI, PSQI, TST (sleep diary and actigraphy), depression, anxiety, and stress. Second phase: Immediate cognitive therapy and mindfulness-based therapy displayed larger reduction on ISI, PSQ, and TST than delayed therapy (maintained results at 3-month follow-up). There was no significant difference between cognitive therapy and mindfulnessbased therapy during second phase.

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Behavior therapy and Behavior therapy þ Constructive worry resulted in improvements on TWT, TST, ISI, APSQ, and WSAS at post-treatment and follow-up. Behavior therapy þ Constructive worry displayed larger reduction on ISI at posttreatment and 2-weeks follow-up, and on APSQ at follow-up. Behavior therapy þ Constructive worry resulted in more responders at post-treatment and follow-up. Both interventions were equally effective on TWT, TST, and WSAS at post-treatment and follow-up.

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€ jmark M, Norell-Clarke A, The cognitive treatment components and therapies of cognitive Please cite this article in press as: Jansson-Fro behavioral therapy for insomnia: A systematic review, Sleep Medicine Reviews (2018), https://doi.org/10.1016/j.smrv.2018.05.001

Harvey et al., 2014 [53]

(continued on next page) 7

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Design

Sample: Size, diagnosis, age (M), % female, % attrition

Treatment type

Treatment delivery

Outcomes

Findings

Quality score

RCT

38, primary insomnia, 21 y, 79%, 13%

(a) Constructive worry (b) Worry monitoring

(a þ b) 1 session, individual format

Sleep diary (SOL, TWT, TST), PSAS, STAIS, actigraphy (SOL, TWT, TST)

Constructive worry resulted in reduction on PSAS-C. Constructive worry demonstrated larger reduction than other group on PSAS-C. No followup.

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RCT

64, insomnia symptoms, 19 e80 y, 42%, 25%

(a) Coping imagery (b Paradoxical intention (c) Sleep information (d) Waitlist control

(a e c) 6 sessions, individual format

Sleep diary (SOL, NAW, TST, SQ, restedness, sleep medication), PSAS, STAI, BDI

Coping imagery resulted in improvements on SOL, PSAS-C, and BDI, and paradoxical intention on SOL, TST, restedness PSAS-C, and BDI. Paradoxical intention and coping imagery displayed larger improvement than the other two groups on SOL. Paradoxical intention, coping imagery and sleep information resulted in larger improvement than waitlist on TST, restedness, and PSAS-C. There were maintained effects for the active groups at 3-months follow-up.

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Distraction Harvey & Payne, 2002 [61]

RCT

50, insomnia symptoms, 22 e23 y, 51%, 18%

(a) Imagery distraction (b) General distraction (c) No instruction

(a e c) 1 session, individual format

Sleep diary (SOL), thought frequency rating, thought discomfort rating

Imagery distraction and general distraction resulted in larger reduction on SOL than control. Imagery distraction led to larger reduction on thought discomfort than control. No follow-up.

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Imagery training Morin & Azrin, 1987 [44]

RCT

27, sleep-maintenance insomnia, 57 y, 67%, 22%

(a) Imagery training (b) Stimulus control (c) Waitlist

(a - b) 4 sessions, group format

Sleep diary (WASO, NAW), BDI, STAI

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Morin & Azrin, 1988 [45]

RCT

28, sleep-maintenance insomnia, 67 y, 63%, 4%

(a) Imagery training (b) Stimulus control (c) Waitlist

(a e b) 6 sessions, group format

Sleep diary (SOL, WASO, NAW, TST, medication), significant-other insomnia ratings, patient insomnia ratings, BDI, STAI

Woolfolk & McNulty, 1983 [49]

RCT

51, sleep-onset insomnia, 43 y, 68%, 14%

(a) Imagery training (b) Imagery training þ Muscle-tension release (c) Somatic focusing (d) Relaxation (e) Waitlist

(a - d) 4 sessions, group format

Sleep diary (SOL, NAW, TST, difficulty falling asleep, SQ, restedness, tiredness, relaxed in bed, difficulty controlling intrusive thoughts), STAI, TAQ

Imagery training displayed reduction on NAW at post-treatment. Stimulus control resulted in larger reduction on WASO than imagery and waitlist groups at post-treatment. Stimulus control displayed larger reduction on BDI than imagery training at post-treatment. Imagery training led to reduction on WASO at 3-month follow-up. Stimulus control resulted in shorter WASO than imagery training at 3 month follow-up (no significant group difference at 12month follow-up). Imagery training resulted in reduction on WASO, medication use and patient insomnia ratings at post-treatment. Stimulus control displayed larger reduction than imagery training on TST and patient insomnia ratings at posttreatment. Imagery training led to reduction on SOL and WASO at 3- and 12-month follow-ups. Imagery training groups showed improvements on SOL, difficulty falling asleep, SQ, restedness and difficulty in controlling intrusive thoughts at posttreatment. Imagery training groups displayed larger reduction on SOL than waitlist, and larger decreases on NAW

Carney & Waters, 2006 [37]

Coping imagery Gould, 1988 [39]

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Table 2 (continued )

Increased visual imagery Nelson & Harvey, 2002 [40]

RCT

31, primary insomnia (sleep-onset difficulties), 19.8e20.9 y, 55%, NA

(a) Cope with imagery before speech threat (b) Cope with verbal thoughts before speech threat

(a e b) 1 session, individual format

Bedtime: Pre- and post-thought speech anxiety questionnaire, post-thought processing questionnaire; waking: SOL, speech anxiety questionnaire, resolution about the speech

Imagery group were more distressed and aroused at bedtime. Imagery group displayed shorter SOL, less anxiety and more comfort about giving the speech, and higher level of resolution on waking. No follow-up.

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Paradoxical intention Espie et al., 1989 [31]

RCT

101, sleep-onset insomnia, 45 y, 67%, 17%

(a) Paradoxical intention (b) Relaxation (c) Stimulus control (d) Placebo (e) No treatment

(a e d) 8 weeks, individual format

Sleep diary (SOL, TST, SQ), ZAS, ZDS, SBRS, ARS

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Fogle & Dyal, 1983 [32]

RCT

35, insomnia symptoms, 41 y, NR, 6%

(a e c) 3 weeks, booklets

Sleep performance anxiety (8-item scale), sleep efficiency, morning restedness

Ascher & Turner, 1979 [33]

RCT

25, primary insomnia, 39 y, 60%, NR

(a) Paradoxical intention: “Give-up-trying” (GUT) (b) Paradoxical intention: “Try-giving-up” (TGU) (c) Control information (a) Paradoxical intention (b) Placebo (c) No treatment

(a e b) 4 sessions, individual format

Sleep diary (SOL, NAW, restedness, difficulty falling asleep)

Ascher & Turner, 1980 [34]

RCT

40, poor sleep, 37 y, NR, NR

(a) Paradoxical intention 1 (b) Paradoxical intention 2 (c) Placebo (d) No treatment

(a e c) 4 sessions, individual format

Sleep diary (SOL, NAW, restedness, difficulty falling asleep, TST)

Broomfield & Espie, 2003 [35]

RCT

34, primary insomnia, 25 y, 56%, 6%

(a) Paradoxical intention (b) Monitoring control

(a e b) 1 session, individual format

Sleep diary (SOL, SE, effort to sleep), SAS, SPAQ, actigraphy (SOL, SE)

Buchanan, 1988 [36]

RCT

51, insomnia symptoms, NR, NR, 35%

(a e b) 3 sessions, individual format

Sleep diary (SOL, SE, morning restedness), SPAS

Gould, 1988 [39]

RCT

64, insomnia symptoms, 19 e80 y, 42%, 25%

(a) Paradoxical intention (b) Quasi-desensitization control (c) Wait-list control (a) Paradoxical intention (b) Coping imagery (c) Sleep information (d) Waitlist control

(a e c) 6 sessions, individual format

Sleep diary (SOL, NAW, TST, SQ, restedness, sleep medication), PSAS, STAI, BDI

Paradoxical intention resulted in reduction on SOL and increase on TST and SQ. Paradoxical intention led to reduction on ZAS, ZDS, and ARS. Paradoxical intention was noted to be inferior to stimulus control the first three weeks on SOL. There was maintained effect for paradoxical intention at four follow-ups (the last at 17 month). Paradoxical intention displayed increased SQ at follow-ups. Both forms of paradoxical intention led to larger reduction in sleep performance anxiety than control. All three groups improved on sleep efficiency. No follow-up. Paradoxical intention resulted in larger reduction than the other groups on SOL, NAW and difficulty falling asleep at post-treatment. No follow-up. Paradoxical intention 1 led to larger reduction than no-treatment group on all outcomes at post-treatment; paradoxical intention 1 displayed larger decrease than paradoxical intention 2 and placebo on SOL, NAW and restedness at post-treatment. No follow-up. Paradoxical intention resulted in larger reduction on sleep effort, SAS, and SPAQ at post-treatment. No follow-up. Paradoxical intention led to larger reduction than waitlist on sleep performance anxiety at post-treatment and 3-week follow-up. Paradoxical intention resulted in improvements on SOL, TST, restedness PSAS-C, and BDI. Coping imagery led to improvements on SOL, PSAS-C, and BDI. Paradoxical intention and coping imagery displayed larger improvement than the other two groups on SOL. Paradoxical intention, coping imagery and sleep information resulted in larger improvement than waitlist on TST, restedness, and PSAS-C. There were maintained effects for the active groups at 3-month follow-up.

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than the other three groups at posttreatment. Imagery training groups resulted in larger reductions on SOL than all the other three groups at 6month follow-up.

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(continued on next page)

10

Design

Sample: Size, diagnosis, age (M), % female, % attrition

Treatment type

Treatment delivery

Outcomes

Findings

Quality score

Ladouceur & GrosLouis, 1986 [42]

RCT

27, insomnia symptoms, 42 y, 67%, NR

(a) Paradoxical intention (b) Stimulus control (c) Sleep information (d) Monitoring control

(a e c) 4 sessions, group format

Sleep diary (SOL)

8

Ott et al., 1983 [46]

RCT

56, sleep-onset insomnia, 18e55 y, 61%, NR

(a) Paradoxical intention (b) Paradoxical intention þ feedback (c) Feedback (d) No treatment

(a e c) 1 session, individual format

Sleep diary (SOL, NAW, SQ, medication), sleep monitoring device (SOL)

Turner & Ascher, 1979 [47]

RCT

50, primary insomnia, 39 y, 50%, NR

(a) Paradoxical intention (b) Stimulus control (c) Progressive relaxation (d) Placebo (e) Waitlist

(a e d) 4 sessions, individual format

Sleep diary (SOL, NAW, restedness, TST, sleep medication)

UCT

28, insomnia symptoms, 24 y, 70%, 29%

(a) Paradoxical intention

(a) 4 sessions, individual format

Sleep diary (11 items), STAI-S, BDI

Paradoxical intention and stimulus control displayed larger reduction on SOL than the other two groups at posttreatment and 2-month follow-up. Paradoxical intention and stimulus control were equally effective at posttreatment and follow-up. Paradoxical intention resulted in reduction on subjective and objective SOL for the first week and this was maintained for the second week. Paradoxical intention þ feedback displayed deterioration on subjective and objective SOL. Feedback only led to reduction on SOL. No follow-up. Paradoxical intention resulted in larger improvement than placebo and waitlist on SOL, NAW, restedness, difficulty falling asleep, and sleep medication at post-treatment; no difference emerged between paradoxical intention, stimulus control, and progressive relaxation at post-treatment. No follow-up. Paradoxical intention resulted in reduction on five sleep diary outcomes (SOL, TST, restedness upon awakening, use of sleep medication, and difficulty falling asleep) at post-treatment. There were maintained improvements at 6week follow-up for SOL, restedness upon awakening, and difficulty falling asleep.

Pennebaker writing intervention Harvey & Farrell, 2003 RCT [41]

45, poor sleep, 22e24 y, 45%, 7%

(a e c) 1 session, individual format

Sleep diary (SOL)

Pennebaker writing intervention led to larger reduction on SOL than no writing condition. No follow-up.

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Mooney et al., 2009 [43]

RCT

28, primary insomnia, 33 y, 64%, 4%

(a) Pennebaker writing intervention (b) General writing (c) No writing (a) Pennebaker writing intervention (b) Monitoring control

(a e b) 1 session, individual format

Sleep diary (SOL), PSAS-C, mental alertness

Pennebaker writing intervention resulted in larger reduction on mental alertness at post-treatment. No followup.

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RCT

47, insomnia disorder, 34 e45 y, 62%, 15%

(a e b) 1 session BT, group format (a e b) 5 sessions of PS or CRES, individual format

Sleep diary (SOL, NAW, WASO, TST, SE, medication or alcohol), ISI, PSQI, SPSIR:S, DBAS, PSWQ

Following full treatment, both groups improved on SOL, NAW, WASO, TST, SE, medication or alcohol, ISI, PSQI, number of responders and remitters, SPSI-R:S, DBAS, and PSWQ at post-treatment and 1-month follow-up. Behavior therapy þ Cognitive restructuring displayed faster reduction on DBAS.

17

Barach, 1982 [62]

a

Problem solving therapy Pech & O'Kearney, 2013 [54]

(a) Behavior therapy þ Problem solving (b) Behavior therapy þ Cognitive restructuring

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Table 2 (continued )

30, poor sleepers, 32e37 y, 50%, NR

(a) Not monitor clock e poor sleepers (b) Monitor clock e poor sleepers

(a - b) 1 session, individual format

Sleep diary (SOL, pre-sleep worry), actigraphy (SOL)

Clock monitors were more likely to be awake due to worry about sleep onset. Clock monitors displayed longer SOL than non-clock monitors (sleep diary and actigraphy). Clock monitors overestimated their SOL more than non-clock monitors. No follow-up.

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Reducing sleep misperception Tang & Harvey, 2004 RCT [56]

42, primary insomnia, 23 e25 y, 65%, 5%

(a - b) 1 session, individual format

Sleep diary (SOL, TST), actigraphy (SOL, TST), APSQ

RCT

48, primary insomnia, 29 e34 y, 56%, 8%

(a - b) 1 session, individual format

Sleep diary (SOL, TST), actigraphy (SOL, TST), APSQ, ISQ, ISI, sleep perception, sleep distress

Visual feedback resulted in larger reduction on subjective SOL and APSQ than control group. Subjective TST increased for both groups. No followup. Visual feedback resulted in larger reduction on APSQ, ISQ, ISI, and sleep distress than verbal feedback. Visual feedback led to more positive sleep perception. Subjective SOL decreased and TST increased for both groups. A reduced discrepancy was noted between subjectively- and objectivelymeasured SOL and TST for both groups. No follow-up.

13

Tang & Harvey, 2006 [57]

(a) Visual feedback: Shown discrepancy between subjective and objective sleep estimates (b) Not shown discrepancy (a) Visual feedback: Shown discrepancy between subjective and objective sleep estimates (b) Verbal feedback about discrepancy

RCT

38, insomnia symptoms, 20 y, 63%, 13%

(a - b) 2 sessions, individual format

Sleep diary (SOL, difficulty falling asleep)

Thought-stopping Villiotis, 1982 [48]

(a) Thought-stopping (b) Awareness condition (c) Monitoring control

Thought-stopping resulted in larger reduction on SOL and difficulty falling asleep than the two other groups. No follow-up.

14

11

Note. APSQ ¼ Anxiety and Preoccupation about Sleep Questionnaire, ARS ¼ Analogue Rating Scale (indexing daytime functioning), ASSQ ¼ Anxious Self-Statement Questionnaire, BAI ¼ Beck Anxiety Inventory, BDI ¼ Beck Depression Inventory, BT-I ¼ behavior therapy for insomnia, CBT-I ¼ cognitive behavior therapy for insomnia, CR ¼ cognitive refocusing, CT-I ¼ cognitive therapy for insomnia, DASS ¼ Depression, Anxiety and Stress Scale, DBAS ¼ Dysfunctional Beliefs and Attitudes about Sleep scale, ISI ¼ Insomnia Severity Index, ISQ ¼ Insomnia Symptom Questionnaire, MFI ¼ Multidimensional Fatigue Inventory, NR ¼ not reported, NAW ¼ number of awakenings, PI ¼ paradoxical intention, PICI ¼ Pre-sleep Intrusive Cognitions Inventory, PS ¼ problem solving, PSAS ¼ Pre-Sleep Arousal Scale, PSAS-C ¼ Pre-Sleep Arousal Scale e cognitive subscale, PSAS-S ¼ Pre-Sleep Arousal Scale e somatic subscale, PSQI ¼ Pittsburgh Sleep Quality Index, PSWQ ¼ Penn State Worry Questionnaire, RCT ¼ randomized controlled trial, SAMI ¼ Sleep Associated Monitoring Index, SAS ¼ Sleep Anxiety Scale, SBRS ¼ Sleep Behavior Self-Rating Scale-modified, SE ¼ sleep efficiency, SES ¼ SelfeEfficacy Scale, SF-36 ¼ SF-36 Health Survey, SQ ¼ sleep quality, SOL ¼ sleep onset latency, SPAQ ¼ Sleep Performance Anxiety Questionnaire, SPAS ¼ Sleep Performance Anxiety Scale, SPSI-R:S ¼ Social Problem-Solving InventoryeRevised: Short-Form, SRBQ ¼ Sleep Related Behaviors Questionnaire, SSS ¼ Stanford Sleepiness Scale, STAI ¼ State-Trait Anxiety Inventory, STAI-S ¼ State-Trait Anxiety Inventory-State, TAQ ¼ Trimodal Anxiety Questionnaire, TST ¼ total sleep time, TWT ¼ total wake time, UCT ¼ uncontrolled trial, WASO ¼ wake after sleep onset, WSAS ¼ Work and Social Adjustment Scale, ZAS ¼ Zung Self-Rating Anxiety Scale, ZDS ¼ Zung Self-Rating Depression Scale. a As a portion of the study participants were good sleepers, they were excluded from the current review. b Of the two studies that were presented in the paper, one investigation was excluded because it did not test a cognitive component that would be feasible to implement in a therapeutic setting.

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Reducing clock monitoring Tang et al., 2007 RCT [58],a,b

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the second investigation [53], CT-I was compared with cognitive behavior therapy (CBT-I) and behavior therapy (BT-I) for those with insomnia disorder. (The CBT-I consisted of standard behavioral techniques plus the treatment content of CT-I). All therapies were administered during eight sessions, but CBT-I had slightly longer sessions than CT-I and BT-I. All therapies reduced insomnia severity, although CBT-I had a greater effect. There were also more responders in CBT-I and BT-I at post-treatment, relative to CT-I. However, there was an increase in the number of responders in CT-I and a decrease in responders in BT-I from post-treatment to follow-up. Also, there was a higher rate of remission in CBT-I than in CT-I at post-treatment (this was not the case at follow-up), and there was an increase in the remission rate in CT-I from post-treatment to follow-up. On sleep diary parameters at post-treatment, BT-I outperformed CT-I on sleep onset latency and wake after sleep onset, and CBT-I and BT-I was superior to CT-I on sleep efficiency. All therapies increased total sleep time. On polysomnography at post-treatment, CBT-I and BTI outperformed CT-I on sleep onset latency and sleep efficiency, and BT-I was superior to CBT-I and CT-I on wake after sleep onset. Finally, all therapies reduced dysfunction and mental health problems. The third study investigated four sessions of standard CBT-I [60] with the addition of four sessions of CT-I or mindfulness [55]. (The CBT-I included the cognitive techniques constructive worry and cognitive restructuring). Both additional treatments after CBT-I were associated with further significant improvements on insomnia severity, objective and subjective total sleep time, wake after sleep onset, and sleep efficiency but there were no differences between the treatments. Together, the results from the three studies suggest that CT-I with a focus on behavioral experiments leads to improvements on a plethora of insomnia-related outcomes, and that it adds further improvements after behavioral insomnia techniques (with or without more traditional cognitive insomnia techniques). A combination of BT-I and CT-I yields stronger effects than either part alone. Whether this is more or less efficient than the addition of mindfulness is a question for future research. To conclude, there is support for the use of CT-I.

instructed to use distraction at bedtime: the first group was asked to employ imagery of a pleasant but non arousing situation and the other group was instructed to distract from worries and concerns but given no instructions on how. (Examples of strategies that the general distraction group employed included going through the day's events, counting, listening to music, or meditating). A third group was instructed to follow their usual bedtime routines. The findings indicated that both groups that had used distraction reported a larger reduction on subjective sleep onset latency, relative to the control group. Also, those who used imagery distraction displayed a greater decrease on thought discomfort than the other conditions. To conclude, there is support for distraction as a technique to shorten sleep onset latency but whether the active mechanism is, as proposed, engaging one's mind so that distressing thoughts will be less likely or the visual thinking itself is unclear. A related study found that worrying in images was superior to verbal worry regarding sleep onset when dealing with a stressor [40]. Participants with primary insomnia were informed at bedtime that they would have to perform a speech in front of a camera the following day. Half of the participants had been given instructions on how to worry in images whereas the other half had been instructed on how to worry in verbal thoughts. Although the image group reported greater distress and higher arousal after the time spent worrying before sleep onset, both groups were equally concerned about their future speech before they fell asleep. The image group reported shorter sleep onset latency the night before the speech and less anxiety about giving the speech during the following day. Together, the studies suggest that thinking in images may be superior to verbal thinking regarding sleep onset latency.

Constructive worry Two studies have investigated the efficacy of constructive worry in volunteers with insomnia disorder or students with primary insomnia [30,37]. In the first study [37], constructive worry was compared with instructions to record worries and complete worry questionnaires. Both interventions consisted of only one session (15 min). Only constructive worry was associated with a significant decrease in cognitive pre-sleep arousal after the intervention, and this was significantly lower than the comparison group. However, there were no significant differences on other outcomes such as state anxiety, and subjective or objective (actigraphy) sleep measures. In the second investigation [30], constructive worry plus behavior therapy (i.e., sleep restriction and stimulus control) was compared with behavior therapy only. Both interventions were administered across four sessions. The results indicated that both interventions produced improvements in total wake time, total sleep time, insomnia severity, worry, and dysfunction. The combined therapy resulted in significantly larger reductions on insomnia severity at mid-treatment, post-treatment and follow-up, and more marked improvements on worry at follow-up. Also, the combined intervention led to more treatment responders, relative to behavioral therapy only. Together, the two studies indicate that constructive worry reduces cognitive arousal. The findings on other outcomes are mixed across the two investigations.

Imagery training Three investigations have examined imagery training in people with sleep-onset or sleep-maintenance insomnia [44,45,49]. In the first study [49], four groups (imagery training, imagery training combined with muscle tension-release, somatic focusing, and progressive relaxation), were compared with a waitlist. All active groups improved on sleep onset latency and tiredness. The imagery training conditions were superior to the other three groups on the number of awakenings, and on sleep onset latency at follow-up but not posttreatment. The second investigation compared imagery training with stimulus control and a waitlist condition [44]. The findings showed that imagery training and stimulus control resulted in significant reductions on the number of awakenings at post-treatment compared to waitlist. However, stimulus control was superior to imagery training on decreasing the duration of awakenings at post treatment and follow-up, and on depression. There were no differences between the groups on state and trait anxiety. In the third study [45], imagery training was compared with stimulus control and a waitlist condition. Both active treatments had significant reductions of time awake during the night and use of sleep medication. Although imagery training was associated with a decrease in sleep onset latency at post treatment, stimulus control was superior. The reductions in sleep onset latency were maintained at follow-up, at which point there was no significant difference between the treatment groups. Stimulus control had superior improvements on total sleep time compared to imagery training at post-treatment. Imagery training was not associated with decreases in the number of awakenings, total sleep time, depression or anxiety. To conclude, the results from the three studies are mixed. Imagery training seem somewhat superior to various forms of somatic relaxation techniques but (mostly) inferior to stimulus control on sleep outcomes.

Distraction and increased visual imagery One study has investigated distraction as a cognitive component for people with insomnia symptoms [61]. Two groups were

Paradoxical intention Eleven studies investigated paradoxical intention in those with insomnia symptoms, sleep-onset insomnia or primary insomnia

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[31e36,39,42,46,47,62]. Overall, the rationale and instructions for paradoxical intention differ slightly across studies. First, we present studies that have investigated the most common form of paradoxical intention administration (type A) [33]. The type A rationale is based on that sleep-related performance anxiety is likely to result in sleep difficulties, mainly sleep-onset insomnia. In the type A administration, the patient is instructed to remain awake for as long as possible under sleep-compatible conditions natural for the onset and maintenance of sleep (e.g., lights out) and not to move around or engage in behavior specifically designed to prevent sleep. In one early study [33], paradoxical intention, placebo and a no-treatment condition were compared. The findings demonstrated that paradoxical intention was superior to the other two groups on sleep onset latency, number of awakenings, and difficulty falling asleep at post-treatment. In a second investigation [33], the rationale is not specifically stated but appears to have been Type A-based (the instructions to the patients randomized to paradoxical intention were nevertheless typical for Type A). In the study, paradoxical intention, stimulus control, relaxation, placebo and waitlist conditions were compared. The findings showed that paradoxical intention was superior to the waitlist on sleep onset latency, number of awakenings, restedness, and medication use at post-treatment, but there were no differences on the outcomes when comparing with stimulus control and relaxation. In a later study [62], paradoxical intention was examined in an uncontrolled study. Paradoxical intention resulted in subjective sleep improvements on approximately half of the sleep diary measures (e.g., sleep onset latency and total sleep time) and some of these improvements were maintained at the 6-week follow-up. Later, paradoxical intention was compared with quasidesensitization and a waitlist condition in patients who had first been matched according to three variables (i.e., performance anxiety, caffeine consumption, and alcohol consumption) and then randomized [36]. Paradoxical intention was superior to the waitlist condition in reducing sleep performance anxiety at post-treatment and follow-up, but no statistical group differences were demonstrated for the three sleep diary measures at the two time-points. The fifth investigation [42] investigated paradoxical intention, stimulus control, sleep information, and a control condition. The findings showed that paradoxical intention and stimulus control resulted in larger reduction on sleep onset latency than the other two groups at post-treatment and follow-up; there were no differences in outcome between paradoxical intention and stimulus control. In a later study [31], paradoxical intention was compared with stimulus control, relaxation, placebo and no treatment. The findings showed that paradoxical intention reduced sleep onset latency and increased total sleep time and sleep quality. Also, paradoxical intention decreased anxiety, depression, and functional impairment. The effect of paradoxical intention was shown to be maintained at follow-ups and one measure further improved (sleep quality). In the final investigation [35], paradoxical intention was compared with a control condition. Paradoxical intention, relative to the control, was superior in decreasing sleep effort, sleep anxiety, and sleep performance anxiety at post-treatment. There were, however, no group differences on the remaining sleep diary parameters. In four studies, the rationale and/or instructions differed compared with the abovementioned investigations. In the first of these studies, the Type A administration was compared with a version with a different rationale-giving (labeled Type B) [34]. The Type B administration is based on the rationale that patients need to become aware of anxiety-provoking thoughts, but the specific instructions are identical with Type A. In the study [34], Type A and Type B paradoxical intention administration were studied alongside placebo and a no-treatment condition. Type A administration

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was superior to no treatment on all outcomes at post-treatment. Also, Type A administration had a better outcome on sleep onset latency, number of awakenings, and restedness than Type B and placebo at post-treatment. In a second study, two versions of paradoxical intention were compared [32]. While half of the participants were given the performance-anxiety rationale (i.e., Type A), the other half was not provided with the Type A rationale but also asked to give up all deliberate sleep efforts, without trying to stay awake longer. Compared with a control condition, both types of paradoxical intention resulted in larger reductions in sleep performance anxiety. All three groups had improved at a similar rate on sleep efficiency. In a later study [39], the Type A rationale was used, but the instructions differed compared with other studies. Instead of the previously described Type A instructions, several paradoxical interventions designed to address each of four hypothesized cognitive components of insomnia were used (i.e., recording thoughts, write a summary of the past day's events, and exaggerate the possible consequences of unresolved problems and negative consequences of sleep loss). When comparing this version of paradoxical intention with coping imagery, sleep information, and a waitlist control, paradoxical intention resulted in improvements on two sleep diary measures as well as on pre-sleep arousal and depression. Also, both paradoxical intention and coping imagery showed larger improvement on sleep onset latency. Compared with the waitlist, the three active conditions had a larger increase on total sleep time. The improvements for paradoxical intention were maintained at the 3-month follow-up. In the fourth and final study [46], Type B (with and without feedback on the participants' sleep onset latency) was compared with feedback only and a no-treatment group. Although paradoxical intention without feedback resulted in improvements on subjective and objective sleep onset latency, paradoxical intention with feedback led to deterioration on sleep onset latency. Pennebaker writing intervention Two investigations have examined the use of the Pennebaker writing intervention in those with poor sleep or primary insomnia [41,43]. In the first study [41], the Pennebaker writing intervention was compared with two control conditions: writing about hobbies and interests in general, and no writing. The only outcome was subjective sleep onset latency. The findings showed that the Pennebaker writing intervention resulted in a larger reduction in sleep onset latency, relative to the no writing group. There was no significant difference compared to the other writing group. In the second investigation [43], the Pennebaker writing intervention was compared with instructions to complete questionnaires on worries in volunteers with primary insomnia. There was only one significant difference between the groups: a larger decrease in mental alertness for those who used the Pennebaker writing intervention, but there were no differences regarding sleep onset latency or presleep arousal. To conclude, there is currently mixed support for the use of the Pennebaker writing intervention in insomnia. Problem solving As there were only one study investigating problem solving in insomnia [54], and this study also investigated cognitive restructuring, the results for both techniques are displayed under Cognitive restructuring. Reducing clock monitoring One investigation examined clock monitoring in relation to sleep disturbance [58]. In the study, poor sleepers were asked to either to monitor or not to monitor the clock while in bed. The findings suggested that clock monitors were more likely to be awake because of pre-sleep worry. Also, clock monitors had longer

€ jmark M, Norell-Clarke A, The cognitive treatment components and therapies of cognitive Please cite this article in press as: Jansson-Fro behavioral therapy for insomnia: A systematic review, Sleep Medicine Reviews (2018), https://doi.org/10.1016/j.smrv.2018.05.001

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sleep onset latency than non-clock monitors (as indexed by sleep diary and actigraphy). Finally, clock monitors overestimated their sleep onset latency more than those who did not monitor a clock; the final finding might be interpreted as a larger sleep misperception in those who monitored the clock. Reducing sleep misperception Two studies examined if behavioral experiments could reduce sleep misperception in those with primary insomnia [56,57]. In the first investigation [56], one group was visually shown the discrepancy between subjective (assessed with sleep diary) and objective (actigraphy) sleep estimates during one session. The other group was not shown the discrepancy. The findings demonstrated that only the group who was visually shown the discrepancy displayed a reduction in subjective sleep onset latency, thereby indicating a decrease in sleep misperception. The shown-discrepancy group also reported a reduction on sleep-related worry, a finding not paralleled in the control group. Both groups displayed an increase in subjective total sleep time. There were no significant changes for the two groups on actigraphy estimates. In the second study [57], a similar methodological approach was used as in Tang and Harvey [56] in that one group was visually shown the discrepancy between subjective and objective sleep estimates during one session. In the second study, however, the control group was given verbal feedback about the discrepancy between subjective and objective sleep estimates. The results showed that only the group who was visually shown the discrepancy displayed a reduction in sleep-related worry, insomnia symptoms, insomnia severity, and sleep distress. Also, the shown-discrepancy group had a larger decrease in sleep misperception, relative to the control group. As in the study by Tang and Harvey [56], there was no significant changes for the groups on objective sleep estimates. Thought stopping In one study, thought stopping was examined in a RCT among participants with insomnia symptoms [48]. Compared with two control conditions, thought stopping was more effective in reducing the two outcomes sleep onset latency and perceived difficulty falling asleep. Discussion Summary of main results The aim was to review the empirical evidence regarding cognitive components and cognitive therapies of CBT-I. The included studies investigated a number of cognitive singlecomponents (i.e., cognitive refocusing, cognitive restructuring, constructive worry, distraction and increased visual imagery, imagery training, paradoxical intention, the Pennebaker writing intervention, problem solving, interventions to reduce clock monitoring and sleep misperception, and thought stopping), a multi-component cognitive program, and cognitive therapy. Although the theoretical framework and content of the components and therapies were often distinct, it should be noted some components were similar (e.g., cognitive refocusing and imagery training). As such, it is difficult to view all of these interventions as separate treatment components. Based on the sheer number of investigations, the methodological quality of studies, and the consistency of results, one main finding was that there is support for paradoxical intention and cognitive therapy. Both interventions have been evaluated with positive results among patients with insomnia disorder in RCTs. Paradoxical intention has been shown to outperform placebo and passive control conditions. Cognitive therapy has been

demonstrated to be efficacious in its own right (although possibly inferior to CBT-I in the acute treatment phase) and effective as an adjunct treatment to behavior therapy. Another main finding was that the following components are promising but need further studies: cognitive refocusing, cognitive restructuring, constructive worry, problem solving, imagery training, and behavioral experiments to reduce clock monitoring and sleep misperception. Due to methodological shortcomings and mixed findings, the effects from the following components are unclear: the cognitive program, coping imagery, distraction and increased visual imagery, the Pennebaker writing intervention, and thought stopping. Also, based on literature that has demonstrated that suppression is associated with psychopathology (i.e., anxiety, depression, and eating disorders) [63,64], it should be emphasized that the clinical benefits of thought stopping in insomnia disorder should be questioned. Methodological considerations and quality of evidence The designs varied between the included studies. The majority of investigations were RCTs or experimentally-oriented studies, but three were uncontrolled investigations [20,59,62] which makes it possible that the observed effects in these studies might be due to uncontrolled factors, such as therapist contact and spontaneous recovery. On the other hand, all three components that were investigated through uncontrolled studies (i.e., paradoxical intention, cognitive therapy, and cognitive refocusing) had also been examined in several RCTs with positive results. Nevertheless, it is important to bear in mind that uncontrolled trials likely exaggerate the efficacy of a therapeutic intervention [65], and that welldesigned RCTs provide more robust estimates of effect. Another design-related issue concerning the identified studies was that few investigations used a placebo condition to control for non-specific factors (e.g., therapist contact and reasonable rationale for the cognitive component) and consisting only of treatment elements without demonstrated efficacy for insomnia disorder [31,33,34,47]. Of note is that all the four studies employing a placebo component evaluated the efficacy of paradoxical intention. Though ethical concerns and the lack of rigorously-developed placebo conditions might hamper the use of such conditions in research on insomnia disorder, the reviewed research field would benefit from being able to minimize possible placebo effects in statistical analyses. A common methodological issue with the analyzed studies was the small sample sizes. Out of the studies that included control conditions, there were on average 17.0 (SD ¼ 10.4) patients per treatment arm. Studies failing to demonstrate any significant differences between treatment arms on specific insomnia symptoms or severity (e.g. SOL or the ISI) had an average of 14.9 (SD ¼ 4.5) patients per treatment arm whereas studies that did find differences had 18.9 (SD ¼ 13.7) participants per arm. Thus, Type 2 errors are likely, especially when active treatments were compared. Only three studies reported power calculations prior to trial start [43,52,53]. The patient characteristics were rather homogeneous and more so for older studies than newer ones. Remarkably, only eleven investigations included participants with insomnia disorder, i.e. primary, secondary, or comorbid insomnia [20,30,40,45,51,53e57,59]. The participants in the remaining studies were categorized as having insomnia symptoms or poor sleep. Of note is that all eleven studies that included patients with insomnia disorder demonstrated improvements on at least one insomnia symptom, whereas four studies that tested cognitive components on participants with subclinical insomnia failed to do so. It is possible that patients with clinical insomnia might benefit more from cognitive components, although the negative findings in some studies may have been

€ jmark M, Norell-Clarke A, The cognitive treatment components and therapies of cognitive Please cite this article in press as: Jansson-Fro behavioral therapy for insomnia: A systematic review, Sleep Medicine Reviews (2018), https://doi.org/10.1016/j.smrv.2018.05.001

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influenced by multiple factors (e.g., sample size and type of outcome). A recommendation for future research is therefore to focus more strongly on patients with insomnia disorder. It is also noteworthy that most early studies (1980e2000) only included patients with sleep onset insomnia. As such, the effects from several cognitive components (e.g., coping imagery) on sleep maintenance insomnia and early awakenings are unknown. Also, most studies to date have excluded participants with comorbid problems, although in reality comorbid problems such as psychiatric diagnoses or chronic pain are more common than “pure” insomnia [66]. The effects from cognitive interventions on more complicated patients are largely unknown but it should be noted that some studies that have included patients with anxiety diagnoses have demonstrated large effects on insomnia, albeit with extended treatment durations (e.g., 19). The needed duration or dose may need to be adjusted in case of comorbidities. Study attrition varied greatly across studies. About one fifth of the investigations did not report attrition. Among those papers that did report attrition rates, a majority of investigations reported a relatively small percentage (0e19%), while five investigations had a percentage of dropouts larger than 20% [36,38,39,44,62]. Descriptions of attrition in the five studies with more than 20% dropouts were that participants stopped their study participation during the treatment phase, that they started using medications during the study period (an exclusion criterion in some trials), that they disliked treatment, or that they reported an illness or need for surgery during the study period. Another issue of methodological diversity regards the differences in dosage, as the treatment lengths ranged between one and 14 sessions (M ¼ 3.4) (for an exception see [20], and individual sessions lasted between 15 and 75 min. Hypothetically, it could be suspected that longer treatments are more efficacious, at least for some components that takes time and effort to implement and that leads to gradual improvement over longer periods of time. It should also be noted that a relatively large part of the identified studies administered the components or therapies at only one session; future research might focus on determining the optimal dose of sessions per component or therapy to reach full efficacy. Related to treatment length is type of treatment delivery. In this review, most studies used an individual treatment format (81%), whereas the remaining investigations administered the components or therapies as group format or self-help formats. Since we did not quantitatively determine the efficacy overall, we are unable to assess potential, differential efficacy from various forms of treatment format. Previous evidence on CBT-I at least support the notion that group and self-help formats are efficacious in their own right [67,68]. An inclusion criterion for the current review was that studies must report insomnia-related outcomes (i.e., nighttime and/or daytime symptomatology). Whereas many investigations did assess nighttime symptoms, usually with a sleep diary, or global symptoms (e.g. with the ISI), fewer studies examined daytime symptomatology. There were also investigations that used a very limited number of outcomes [41,42,48]. A related limitation was that only nineteen studies (59%) reported on the cognitive processes that the component or therapy was intended to reverse [20,30,32,35e40,43,49,51,52,54,56e59,61]. Though efficacy on insomnia symptomatology is crucial to demonstrate, it is also important to show that the cognitive intervention has an impact on the proposed cognitive processes (e.g., reduction on performance anxiety for paradoxical intention and worry for cognitive therapy). The length of assessment varied greatly across studies. In total, only fifteen studies (47%) assessed efficacy at follow-ups [20,30,31,36,38,39,42,44,45,49,51,53,54,55,59,62]. Also, in two studies, the length of the follow-up period was limited to less than

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one month [30,38]. The absence of follow-ups with reasonable length for approximately half of the studies makes conclusions difficult to draw regarding the long-term benefits for several of the components included in this review; this appears particularly evident for cognitive refocusing, constructive worry, distraction, increased visual imagery, the Pennebaker writing intervention, reducing clock monitoring and sleep misperception, and thought stopping. On the other hand, long-term follow-ups have been used in studies investigating the cognitive program, cognitive restructuring, cognitive therapy, coping imagery, imagery training, paradoxical intention, and problem-solving; though not a sign of efficacy in itself, those components and therapies have at least been investigated over longer periods of time. As a final note, it is important to mention that the quality assessment demonstrated that the quality of the studies can be viewed as moderate on average (mean: 13.1 points). However, for several cognitive components, none of the studies examining those interventions exceeded the quality score mean; this was apparent for the cognitive program, coping imagery, distraction, increasing visual imagery, the Pennebaker writing intervention, reducing clock monitoring, and thought stopping. It should also be pointed out that the quality scores for studies evaluating paradoxical intention were limited (range 8e13 points), possibly due to that the reporting standards in the 1970's and 1980's were not as formalized as they are now. Thus, due to the restricted quality scores for paradoxical intention, we believe that it is reasonable to regard paradoxical intention as resulting in positive effects but that these improvements should be viewed in light of the extant studies with low-to-moderate quality. Finally, the quality of four studies were rated as high (i.e., 75% of the maximum score or more) [52e55]. This implies that a few cognitive components and therapies have been examined in well-designed studies and enables stronger conclusions. As a result of the well-designed investigations, stronger conclusions can be drawn particularly for cognitive therapy [53,55]. Though two additional studies were rated as with high quality, stronger conclusions are limited for 1) cognitive restructuring and problem-solving by being examined in only study and without a comparison group (e.g., waitlist or placebo condition) [54] and 2) cognitive refocusing by being explored among participants with subclinical insomnia (i.e., insomnia symptoms), with no follow-up assessment, and the somewhat mixed evidence across the three studies investigating cognitive refocusing. Putative mechanisms If cognitive components and therapies lead to improvement in insomnia symptomatology, it will be vital to investigate the mechanisms through which this occurs. As stated above, roughly half of the included studies (k ¼ 19) included measures of cognitive processes. Based on the nineteen studies, evidence indicates that the reduction of the following processes might act as possible mechanisms: 1) intrusive cognitions for the cognitive program [51], 2) problem-solving ability, unhelpful beliefs about sleep, and worry for cognitive restructuring and problem-solving [54], 3) unhelpful beliefs about sleep, worry, cognitive pre-sleep arousal, attentional bias and monitoring, and safety behaviors for cognitive therapy [20], 4) cognitive pre-sleep arousal and worry for constructive worry [30,37], 5) pre-sleep arousal for coping imagery [39], 6) thought discomfort for distraction [61], 7) resolution for increased visual imagery [40], 8) sleep effort, sleep performance anxiety, and mental alertness for paradoxical intention [32,35,36,39,43], 1) presleep worry for reducing clock monitoring [58], and j) worry for decreasing sleep misperception. It is however important to note that all nineteen investigations analyzed the cognitive processes as outcomes and not as mediators, thereby limiting the possibility to

€ jmark M, Norell-Clarke A, The cognitive treatment components and therapies of cognitive Please cite this article in press as: Jansson-Fro behavioral therapy for insomnia: A systematic review, Sleep Medicine Reviews (2018), https://doi.org/10.1016/j.smrv.2018.05.001

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draw strong conclusion concerning putative mechanisms [69]. It is also important to emphasize that some studies failed to show that cognitive processes were modified following treatment: pre-sleep arousal for cognitive refocusing [38,52,59] and difficulty controlling intrusive thoughts for imagery training [49]. In a recent study, cognitive mediators were analyzed for CT-I and BT-I [17]. The findings showed that worry, unhelpful beliefs, and monitoring for sleep-related threat mediated outcomes for both CT-I and BT-I. It is thus possible that cognitive processes are important treatment targets not only for cognitive components but also for more behaviorally-oriented interventions. On the basis of these findings, it seems apparent that cognitive processes are often modified as expected through cognitive components and therapies. Whether or not these processes work as mechanisms of change is, however, mainly unknown. Limitations of the current review There are a number of methodological limitations in the current review. First, the included studies displayed high levels of clinical (e.g., diagnosis vs poor sleep) and methodological (e.g., design, outcome measures, and interventions) diversity. Thus, the current review is limited by this diversity, and our conclusions should therefore be interpreted with caution. Second, due to a small number of studies per cognitive component or therapy, we did not perform a quantitative assessment of efficacy (i.e., a meta-analysis). A possible exception to this rationale is paradoxical intention, for which eleven studies were identified in the search process. Third, the current review did not formally assess treatment-relevant domains in the included studies that might have importance for the interpretation of findings. For example, the examined components and therapies might differ in terms of acceptability, adherence rates, credibility and expectancy ratings, adverse events, and perceived usefulness. Finally, regarding the study quality assessment, it should be emphasized that the majority of the eleven assessed domains concerned elements of study reporting (e.g., randomization procedure clearly described). Since fewer study quality items were directly related to design characteristics (e.g., sample size justified), a potential risk with our quality assessment is that scores for less well-designed studies might have been inflated in relation to more well-designed investigations.

this review analyzed cognitive processes purely as outcomes, it is vital to move the field forward towards a focus on mediational analyses. This would pave way for evidence-based explanations for how or why cognitive components and therapies produce change [70]. The exploration of moderators is another area for scrutiny [69]. On a conceptual level, moderators identify on whom and under what circumstances treatments have different effects. In relation to this review, it is possible that socioedemographic parameters, symptomatic burden, or cognitive processes moderate the efficacy of cognitive components and therapies. Conclusions We conclude that there is support for a few components and therapies for patients with insomnia disorder. More specifically, evidence suggest that paradoxical intention and cognitive therapy appears efficacious in their own right. There are also other cognitive components that appears promising. Although that the research field has grown substantially over the past decade, several methodological limitations hamper the possibility to draw strong conclusions. Based on that several cognitive components and therapies seems efficacious and promising, future research is needed to gain insight into their efficacy, mechanisms of change, and moderators.

Practice points  There is evidence of efficacy for two cognitive components and therapies: paradoxical intention and cognitive therapy. Both paradoxical intention and cognitive therapy (as formulated by Allison G. Harvey) have been validated in several trials but are not integrated in current CBT-I.  Several other cognitive components and therapies are promising but there is a need of more robust studies before more firm conclusions can be drawn.  The most commonly used cognitive CBT-I component, cognitive restructuring, has been scarcely investigated.  Until there are more studies, we recommend the use of CBT-I manuals whose efficacy have been evaluated or include sufficiently evaluated cognitive components.

Future directions There are several areas that need further scientific scrutiny. Methodologically more robust study designs when investigating cognitive components and therapies are warranted. Specifically, attempts to compare several active treatments needs to be preceded by power calculations. Further, investigations should aim to assess efficacy on a broad set of outcomes, such as sleep diaries, insomnia-related measures, and putative mechanisms of change. Future studies should also aim to assess treatment-relevant domains, such as acceptability, adherence rates, and adverse events. Another similar area for future research is using dismantling designs to examine the unique as well as the synergetic effects of cognitive techniques combined with behavioral techniques in CBTI. The potential benefits to clinical practice of dismantling designs is the identification of the necessary and sufficient components of treatment, thereby providing important insight into how insomnia could be managed more effectively. Finally, studies are needed that explore the optimal dose of cognitive components and therapies and possible differential effects for various treatment formats (e.g., individual vs group format). Two final important areas for future research are putative mechanisms (mediators) and moderators. As all investigations in

Research agenda Future research should aim to:  Compare the effects of cognitive techniques in sufficiently statistically powered RCTs with follow-up assessments and test various doses and delivery formats of the components.  Test the effects of cognitive interventions on sleep diaries, insomnia measures, and putative mechanisms of change.  Dismantle the cognitive techniques in commonly used CBT-I packages so that the unique as well as the synergetic effects of cognitive components combined with behavioral techniques can be established.  Investigate whether several factors (e.g., socio edemographic parameters, insomnia disorder versus comorbid insomnia versus subclinical insomnia, and global symptomatic burden) moderate the efficacy of cognitive components and therapies.

€ jmark M, Norell-Clarke A, The cognitive treatment components and therapies of cognitive Please cite this article in press as: Jansson-Fro behavioral therapy for insomnia: A systematic review, Sleep Medicine Reviews (2018), https://doi.org/10.1016/j.smrv.2018.05.001

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Acknowledgments We wish to express our gratitude to the two librarians at Karolinska Institute Library (Klas Moberg and Carl Gornitzki) for carrying out the database search and to Dr. Pernilla Garmy at Kristianstad University for evaluating the study quality of one of the included studies. The authors have no conflicts of interest. Appendix A. Supplementary data Supplementary data related to this article can be found at https://doi.org/10.1016/j.smrv.2018.05.001. References [1] American Academy of Sleep Medicine. International classification of sleep disorders. 3rd ed. Darien, IL: American Academy of Sleep Medicine; 2014. [2] American Psychiatric Association. Diagnostic and statistical manual of mental disorders. 5th ed. Washington, DC: American Psychiatric Association; 2013. [3] Morin CM, Drake CL, Harvey AG, Krystal AD, Manber R, Riemann D, et al. Insomnia disorder. Nat Rev Dis Prim [Internet] 2015;1:15026. Available from: https://doi.org/10.1038/nrdp.2015.26. [4] Morin CM. Cognitive-behavioral therapy of insomnia. Sleep Med Clin 2006;1(3):375e86. [5] Trauer JM, Qian MY, Doyle JS, Rajaratnam SMW, Cunnington D. Cognitive behavioral therapy for chronic insomnia: a systematic review and metaanalysis. Ann Intern Med 2015;163(3):191e204. [6] van Straten A, van der Zweerde T, Kleiboer A, Cuijpers P, Morin CM, Lancee J. Cognitive and behavioral therapies in the treatment of insomnia: a metaanalysis. Sleep Med Rev [Internet] 2017;38:3e16. Available from: http:// www.ncbi.nlm.nih.gov/pubmed/28392168. [7] Riemann D, Baglioni C, Bassetti C, Bjorvatn B, Dolenc Groselj L, Ellis JG, et al. European guideline for the diagnosis and treatment of insomnia. J Sleep Res [Internet] 2017;26:675e700. Available from: http://doi.wiley.com/10.1111/jsr. 12594. [8] Vitiello MV, McCurry SM, Rybarczyk BD. The future of cognitive behavioral therapy for insomnia: what important research remains to be done? J Clin Psychol [Internet] 2013;69(10):1013e21. Available from: https://doi.org/10. 1002/jclp.21948. [9] Schwartz DR, Carney CE. Mediators of cognitive-behavioral therapy for insomnia: a review of randomized controlled trials and secondary analysis studies [cited 2012 Jul 28] Clin Psychol Rev [Internet] 2012 Jul;32:664e75. Available from: http://linkinghub.elsevier.com/retrieve/pii/S0272735812000955. *[10] Harvey AG, Tang NKY, Browning L. Cognitive approaches to insomnia. Clin Psychol Rev 2005;25:593e611. *[11] Belanger L, Savard J, Morin C. Clinical management of insomnia using cognitive therapy. Behav Sleep Med [Internet] 2006;4(3):179e202. Available from: http://www.tandfonline.com/doi/abs/10.1207/s15402010bsm0403_4. [12] Miller CB, Espie CA, Epstein DR, Friedman L, Morin CM, Pigeon WR, et al. The evidence base of sleep restriction therapy for treating insomnia disorder. Sleep Med Rev [Internet] 2014;18(5):415e24. Available from: http://www. sciencedirect.com/science/article/pii/S1087079214000161. *[13] Espie CA. Insomnia: conceptual issues in the development, persistence, and treatment of sleep disorder in adults. Annu Rev Psychol 2002;53:215e43. *[14] Espie CA. Understanding insomnia through cognitive modelling. Sleep Med 2007;(Suppl. 4):8. *[15] Harvey AG. A cognitive model of insomnia. Behav Res Ther 2002;40:869e93. *[16] Lundh LG, Broman JE. Insomnia as an interaction between sleep-interfering and sleep-interpreting processes. J Psychosom Res [Internet] 2000 Nov;49(5):299e310. Available from: http://www.ncbi.nlm.nih.gov/pubmed/ 11164054. langer L, Morin CM. Mediators and treatment matching [17] Harvey AG, Dong L, Be in behavior therapy, cognitive therapy and cognitive behavior therapy for chronic insomnia. J Consult Clin Psychol [Internet] 2017;85(10):975e87. Available from: http://doi.apa.org/getdoi.cfm?doi¼10.1037/ccp0000244% 0Ahttp://www.ncbi.nlm.nih.gov/pubmed/28956950. [18] Hiller RM, Johnston A, Dohnt H, Lovato N, Gradisar M. Assessing cognitive processes related to insomnia: a review and measurement guide for Harvey's cognitive model for the maintenance of insomnia. Sleep Med Rev [Internet] 2015;23(September 2014):46e53. Available from: https://doi.org/10.1016/j. smrv.2014.11.006. [19] Clark DM, Ehlers A, Hackmann A, McManus F, Fennell M, Grey N, et al. Cognitive therapy versus exposure and applied relaxation in social phobia: a randomized controlled trial. J Consult Clin Psychol [Internet] 2006;74(3): 568e78. Available from: http://doi.apa.org/getdoi.cfm?doi¼10.1037/0022006X.74.3.568.

* The most important references are denoted by an asterisk.

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€ jmark M, Norell-Clarke A, The cognitive treatment components and therapies of cognitive Please cite this article in press as: Jansson-Fro behavioral therapy for insomnia: A systematic review, Sleep Medicine Reviews (2018), https://doi.org/10.1016/j.smrv.2018.05.001