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Dream content and intrusive thoughts in Obsessive-Compulsive Disorder
Author’s Accepted Manuscript Dream content and intrusive thoughts in ObsessiveCompulsive Disorder Simone Cavallotti, Cecilia Casetta, Valentina Fanti, Edoardo G. Ostinelli, Rebecca Ranieri, Irene Vanelli, Armando D’Agostino www.elsevier.com/locate/psychres
PII: DOI: Reference:
S0165-1781(16)30185-8 http://dx.doi.org/10.1016/j.psychres.2016.08.008 PSY9879
To appear in: Psychiatry Research Received date: 1 February 2016 Revised date: 28 July 2016 Accepted date: 3 August 2016 Cite this article as: Simone Cavallotti, Cecilia Casetta, Valentina Fanti, Edoardo G. Ostinelli, Rebecca Ranieri, Irene Vanelli and Armando D’Agostino, Dream content and intrusive thoughts in Obsessive-Compulsive Disorder, Psychiatry Research, http://dx.doi.org/10.1016/j.psychres.2016.08.008 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting galley proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Dream content and intrusive thoughts in Obsessive-Compulsive Disorder.
Simone Cavallotti, M.D. a,b, Cecilia Casetta, M.D. a,b, Valentina Fanti, M.D. a,b, Edoardo G. Ostinelli, M.D.a,b, Rebecca Ranieri, M.D.a,b, Irene Vanelli, Ph.D. c, Armando D’Agostino, Ph.D. a,b,*
a
Department of Health Sciences, Università degli Studi di Milano, Milan, Italy b c
Department of Mental Health, San Paolo Hospital, Milan, Italy Department of Psychiatry, San Raffaele Hospital, Milan, Italy
* Corresponding author at: Department of Mental Health, San Paolo Hospital, Via A. Di Rudinì 8, Milan, Italy; telephone: (+39) 0281844516; fax: (+39) 0281844026; e-mail address: [email protected] (A. D’Agostino).
ABSTRACT Although central to any exhaustive theory of human subjectivity, the relationship between dream and waking consciousness remains uncertain. Some findings suggest that dream consciousness can be influenced by severe disorders of thought content. The suppression of unwanted thoughts has been shown to influence dream content in healthy individuals. In order to better define this phenomenon, we evaluated the persistence of obsessive/compulsive themes across the dream and waking cognition of OCD patients and in a control group of healthy subjects. Participants were administered a shortened version of the Thematic Apperception Test to produce a waking fantasy narration, and were trained to keep a dream diary. Dream and waking narrative contents were analyzed in order to recognize obsessive/compulsive themes, and to calculate Mean Dream Obsession/Compulsion (MDO, MDC) and Mean TAT Obsession/Compulsion (MTO, MTC) parameters. No
differences were found between the two populations in terms of MDO, MDC, MTO, nor MTC. Density of obsessive and compulsive themes were significantly higher in dream reports than in waking narratives for both groups. No correlation was observed between MDO/MDC scores and Y-BOCS obsession/compulsion scores in the OCD group. These findings strengthen the discontinuity hypothesis, suggesting that ruminative aspects of cognition are somehow interrupted during dream activity.
KEYWORDS Dream content; Intrusive thoughts; Obsession; Continuity hypothesis.
1. Introduction Abnormal dream content is seldom considered of clinical utility in contemporary psychiatric practice. However, some studies suggest that abnormal, disorder-specific dreams are reported by most subjects diagnosed with a mental disorder (Beauchemin and Hays, 1995; Sauteraud and Menny, 1997; Schredl and Engelhardt, 2001; Cartwright et al., 2006; Lusignan et al., 2009; Zanasi et al., 2011). Although hypotheses on the relationship between dream and waking experiences have been proposed, results from this field of research remain sparse (Kröner-Borowik et al., 2013). The poor understanding of mechanistic links between psychiatric diagnoses, sleep abnormalities and chronobiological disruptions contributes to the lack of certainty (Wulff et al., 2010). One previous study from our group found that some delusional themes recur within the dreams of acute inpatients diagnosed with
affective and non-affective psychoses (D’Agostino et al., 2013). This finding suggests that severe disorders of thought content may influence the dream experience. Obsessive-Compulsive Disorder (OCD) is a clinical condition in which the hyperactivity of the orbito-frontal cortex (OFC), the anterior cingulate cortex (ACC) and the basal ganglia determines intrusive, distressing thoughts coupled with ritualistic behaviours (Paus, 2001; Whiteside et al., 2004). The study of continuity/discontinuity of obsessive/compulsive contents across wakefulness and dreams in this population yielded inconsistent results (Sauteraud et al., 2001; Kuelz et al., 2010). Whether or not obsessive thoughts persist within patients’ dreams and to which extent remains unclear. Given the peculiar, distressing nature of waking thought in this population, a clarification of its relationship with dream content seems necessary. The main objective of this study was to evaluate the persistence, if there is one, of obsessive/compulsive themes across the dream and waking cognition of OCD patients. Given the paucity of previous findings, we made no specific prediction over the content analysis of dreams in OCD patients.
2. Methods
2.1 Participants All patients diagnosed with Obsessive-Compulsive Disorder (OCD sample) according to DSM-5 criteria (American Psychiatric Association, 2013), who accessed the OCD outpatient clinics of the San Raffaele and San Paolo Hospital in Milan, Italy, were asked to participate. All participants were unpaid volunteers, and informed consent was obtained from all subjects after detailed explanation of the study purpose and
design. 18 subjects were randomly chosen from a previously implemented database of healthy control subjects from the general population (control sample). All relevant demographic data of the experimental samples are reported along with clinical characteristics in Table 1.
OCD sample Control sample p (n=18) (n=18) Male 10 (55%) 9 (50%) n.s. Female 8 (45%) 9 (50%) Age (years) 38.4 ± 11.1 43.6 ± 16.6 n.s. Education (years) 13.4 ± 3.6 14.7 ± 3.5 n.s. Age of onset 18.5 ± 9.3 Y-BOCS total score 28.9 ± 7.5 Y-BOCS obsessions 15.0 ± 3.6 Y-BOCS compulsions 13.9 ± 4.5 HDRS tot score 7.7 ± 4.8 Reported dreams 58 67 Reported fantasies 126 124 SSRI 10 (56%) Fluvoxamine 7 Sertraline 3 Paroxetine 2 SNRI 2 (11%) Duloxetine 1 Venlafaxine 1 TRICYCLIC 5 (28%) Clomipramine 5 SGA 7 (39%) Risperidone 3 Olanzapine 2 Aripiprazole 1 Quetiapine 1 BENZODIAZEPINE 5 (28%) Table 1: Sociodemographic and clinical data of the experimental populations. OCD: Obsessive Compulsive Disorder; Y-BOCS: Yale-Brown Obsessive Compulsive Scale; HDRS: Hamilton Depression Rating Scale.
Exclusion criteria for all participants were a present or past history of serious medical or neurological diseases, sleep disorders, mental retardation, substance
abuse, perinatal injury, or cranial trauma. An additional exclusion criterion for the OCD sample was a present history of depressive symptoms, as confirmed by a Hamilton Depression Scale (HAM-D) score > than 17 in all selected patients. Family history of a major mental disorder was an adjunctive exclusion criterion for the control sample. None of the patients included in the study were drug-naïve. Various combinations of psychotropic agents were administered to all patients during the week in which the experimental material was collected.
2.2 Clinical assessment Clinical diagnoses were confirmed with the Mini-International Neuropsychiatric Interview (M.I.N.I.). Hamilton Depression Rating Scale (HDRS) score < than 17 confirmed the absence of clinically relevant depression in the OCD sample. Clinical assessment was performed using the Yale-Brown Obsessive Compulsive Scale (YBOCS). Available reference values indicate that OCD patients’ clinical condition could be considered severe (Goodman and Price, 1992). The scales were carried out during the week in which patients were asked to keep a dream diary. Y-BOCS analysis of the control group were not performed as the scale was not administered to controls.
2.3 Dream report and waking fantasy collection Participants were trained to keep a dream diary where each morning they reported dreams from the previous night. Subjects who successfully reported at least one dream were then administered a projective test used to elicit waking fantasy stories: the Thematic Apperception Test (TAT) consists of a broad set of figures,
differentiated into groups of 20, according to sex and age. Seven figures were used to elicit the subjects’ projections (1, 3GF/3BM, 6GF/6BM, 9GF/9BM, 12F/12M, 15, 18GF/18BM); a shortened version of the test has been used because the cards were employed as an experimental stimulus to produce stories and not as a standardized projective test (Fiss et al., 1966; D’Agostino et al., 2010; Kramer et al., 2011; Cavallotti et al., 2014). The test was administered in the morning, and the instructions conformed to the standardized TAT procedure (Teglasi, 2001); all waking narratives were taperecorded and then transcribed.
2.4 Scoring procedure Two trained judges (S.C. – R.R.) with experience in administration and elaboration of the Y-BOCS, analyzed the dream material and the waking narratives of the two groups to identify themes from the obsessions and compulsions by using the Y-BOCS checklist. This scoring procedure was performed and reported in a previous study by Sauteraud et al. (2011). Both judges were blind to the authors of the narrative productions and to their diagnoses. First, all narratives were randomly divided and the judges independently scored 125 waking narratives and 62 dream reports each; then each judge checked the other’s scoring and discussed any divergent opinion until a consensus was reached. Obsessive/compulsive themes were quantified as follows:
(i) One point was assigned for each obsessive or compulsive theme identified.
(i) For each subject, the sum of all obsessive themes scored in dreams was divided by the number of available dream reports (Mean Dream Obsession, MDO). The same procedure for compulsive themes yielded a Mean Dream Compulsion (MDC) index.
(i) Following the same procedure, a Mean TAT Obsession (MTO) and a Mean TAT Compulsion (MTC) index was developed for each subject.
2.5 Statistical Analyses A two-way Analysis of Variance (ANOVA) for repeated measures was performed to assess the effect of diagnosis on the average number of words in dream and TAT reports; parametric analyses were chosen given the normal distribution of data. Two one-way ANOVAs were run to independently estimate the effect of the OCD diagnosis on the presence of obsessive and compulsive themes in dreams. A twoway ANCOVA was then performed to estimate the effect of the OCD diagnosis on the amount of obsessive elements identified in the dreams and waking fantasies with the average number of words as a covariate. The same procedure was then used to determine the effect of the OCD diagnosis on the compulsive themes scored. Finally, a bivariate correlation was used within the OCD population to investigate the trend of the content variables in relationship to the psychopathological scores obtained with the Y-BOCS.
3. Results Dreams were found to be on average three times longer than the waking narratives within the OCD population and about two times longer in healthy subjects
[F(1,34)=33.542, p < 0.001]; however, the interaction of average word count per diagnosis was not found to be statistically significant [F(1,34)=4.00, p = n. s.]. Figure 1 shows obsessive/compulsive themes scored in the dreams and waking fantasies of OCD patients and healthy controls. No differences were found between the two populations in terms of Mean Dream Obsession [F(1,34)=0.138, p = n. s.]. Likewise, the two populations were not found to differ significantly in terms of Mean Dream Compulsion [F(1,34)=0.004, p = n. s.]. Furthermore, no statistically significant difference was found between the two populations in terms of Mean TAT Obsession [F(1,32)=0.246, p = n. s.] and Mean TAT Compulsion [F(1,32)=0.448, p = n. s.]. The density of obsessive themes was clearly found to be higher in the dream reports than in the narratives elicited by the TAT tables for both groups [F(1,32)=7.484, p < 0.05]; this effect was correlated to the average word count of the different narratives, which was higher for dreams [F(1,32=7.947, p < 0.01]. The amount of compulsive themes was slightly but significantly higher in the dream reports than in the waking fantasies of both groups [F(1,32)=6.416, p < 0.05], an effect that was found to be independent of the average word count. Within the patient group, no correlation was observed between waking Y-BOCS obsessions/compulsions scores and the number of obsessive/compulsive themes identified in their dream reports.
4. Discussion
4.1 Discontinuity of obsessive/compulsive content across wakefulness and dreams
78% of OCD patients and 83% of healthy control subjects reported at least one dream in which obsessive themes were identified, whereas compulsions and rituals recurred in the dreams of a lower number of subjects (38% of OCD patients and 66% of healthy controls). The intrusive quality of cognition, also belonging to obsessive intrusive thoughts, might be an adaptive aspect of human nature (Salkovskis, 1989; Clark and Purdon, 1995). The lack of differences between the two populations excludes a specific effect of the OCD diagnosis on the amount of obsessive/compulsive themes in dreams. This finding is in line with one previously published study, in which the dreams of OCD patients were not found to differ substantially from those of healthy control subjects (Sauteraud et al. 2001). On the contrary, Kuelz et al. (2010) found a high frequency of compulsive content before inpatient treatment. The absence of correlation between waking Y-BOCS scores and Mean Dream Obsession/Mean Dream Compulsion scores suggests that the pathological repetitiveness observed in wakefulness is somehow interrupted during dream sleep. Taken as a whole, these findings fail to support the continuity hypothesis, according to which dreams reflect waking-life experiences (Domhoff, 1996). The high rate of obsessive/compulsive elements observed in both our samples suggests that such themes could be more characteristic of physiological dreaming than previously thought. Hyperactivity of ACC, OFC and basal ganglia found both in OCD (Paus, 2001; Whiteside et al., 2004) and during REM sleep (Braun et al., 1997; Nofzinger et al., 1997) could justify the presence of obsessive and ritualistic thoughts that were observed in both the elicited waking reports and in the dream diaries. This shared pattern of neuro-functional activation across states raises the possibility of intriguing speculative hypotheses. Indeed, REM dreams have been proposed to
serve a mnemonic function by elaborating and associating waking experiences into vivid images (Llewellyn, 2013; Llewellyn, 2015). Tulving et al. (1996) suggest that novelty (i.e., non-habitual, “off script” activities) determines the extent of elaborative encoding. Therefore, one might speculate that only novel daytime experiences are associated in dreams, whereas OCD behavior is repetitively associative during wakefulness. In this light, some aspects of the disorder might reflect a compensatory mechanism for reduced associative activity during REM sleep dreaming. In terms of sleep architecture, reduced REM sleep latency and increased REM sleep density are also commonly reported in this population. Indeed, one study found that a small subgroup of OCD patients experienced sleep onset REM periods (Kluge et al., 2007). However, one recent meta-analysis (Nota et al., 2015) failed to confirm abnormalities of REM sleep in these subjects and no direct inference from our sample can be done due to the lack of polysomnographic data. Furthermore, the majority of OCD patients were on treatment with drugs that tend to suppress both Slow Wave and REM Sleep (Argyropoulos and Wilson, 2005; Achermann and Borbély, 1987; Borbély et al., 1985; Gaillard and Tissot, 1973). In order to better address the relationship between brain activity and obsessive/compulsive mechanisms during wakefulness and sleep, future studies should investigate sleep architecture and oneiric activity in OCD patients. Indeed, depressed patients have been shown to experience changes in dream contents that reflect their clinical status (Cartwright et al. 1998), which is not known for OCD. Furthermore, the effect of antidepressant drugs on the emotional tone of dream mentation has been investigated (Schredl et al. 2009), although there are no studies on the effect of these drugs on the dreams of OCD patients. In general, Selective Serotonin Reuptake Inhibitors (SSRIs) are thought to intensify dreaming
whereas tricyclic antidepressants increase positive dream emotions (Tribl et al., 2012), two aspects that do not appear relevant to the main findings of our study. Nonetheless, further studies are needed to confirm our preliminary observations in drug-naïve OCD patients. Despite typical recall rates for nighttime dreams (80% and 43% respectively) suggests that dreaming mentations collected in a diary come preferentially from REM phase (Carr & Nielsen, 2015), EEG studies are needed to characterize better the origin; formal differences in form (Noreika et al. 2009) and length (Blagrove et al. 2011) have been investigated.
4.2 Methodological limitations Several limitations should be considered in discussing these preliminary results. First of all, enrolled patients were on treatment with psychoactive drugs which might have influenced several aspects of dreams and waking fantasies. Given the broad variety of drugs administered to patients (SSRIs, tricyclics, benzodiazepines, and mood stabilizers), specific effects could not be studied in comparison to the control group. Antidepressants, antipsychotics, mood stabilizers, anxiolytics and hypnotics are all known to influence several aspects of sleep architecture in highly variable ways (DeMartinis and Winkour, 2007). Second, participants completed their diaries in different sleep conditions. Whereas most OCD patients and all controls reported dreams in a home setting, most acutely psychotic patients were hospitalized at the time of data collection. Indeed, dream recall frequency, length of reports and content variables have been found to vary across experimental settings (Schredl, 2007). Finally, the stages of sleep from which the dreams derive were not investigated.
Reduction of total sleep time, sleep efficiency and subjective sleep quality have been found to recur in OCD patients (Paterson et al., 2013).
4.3 Conclusions In conclusion, the results of this study weigh against the continuity hypothesis, suggesting that sleep somehow interrupts the mental repetitions that phenomenologically define OCD. Although patients affected by the disorder continuously attempt to control their distressing thoughts, these do not appear to emerge in dreams significantly. Further studies are needed to clarify whether obsessive, ritualistic thought processes characterize physiological dreaming.
Acknowledgement
Role of funding sources None.
Contributors A.D’A. and V.F. designed the study and wrote the protocol. C.C. conducted literature searches and provided summaries of previous research studies. I.V. recruited subjects at the San Raffaele Hospital and V.F. recruited subjects at the San Paolo Hospital. S.C. and R.R. administered evaluation scales and performed analysis on the narratives. E.G.O. conducted the statistical analysis. A.D’A. and S.C. co-wrote the first draft of the manuscript and all Authors contributed to and have approved the final manuscript.
Conflict of interest All authors declare that they have no conflicts of interest.
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Figure 1: Obsessive/compulsive themes scored in the dreams and waking fantasies of OCD patients and healthy controls. MDO: Mean Dream Obsession; MDC: Mean Dream Compulsion; MTO: Mean TAT Obsession; MTC: Mean TAT Compulsion.
HIGHLIGHTS Several findings suggest that dream consciousness can be influenced by severe disorders of. thought content. Our findings appear to strengthen the discontinuity hypothesis between dream and wake. experiences. The ruminative aspects of cognition are somehow interrupted during dream activity.
PII: DOI: Reference:
S0165-1781(16)30185-8 http://dx.doi.org/10.1016/j.psychres.2016.08.008 PSY9879
To appear in: Psychiatry Research Received date: 1 February 2016 Revised date: 28 July 2016 Accepted date: 3 August 2016 Cite this article as: Simone Cavallotti, Cecilia Casetta, Valentina Fanti, Edoardo G. Ostinelli, Rebecca Ranieri, Irene Vanelli and Armando D’Agostino, Dream content and intrusive thoughts in Obsessive-Compulsive Disorder, Psychiatry Research, http://dx.doi.org/10.1016/j.psychres.2016.08.008 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting galley proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Dream content and intrusive thoughts in Obsessive-Compulsive Disorder.
Simone Cavallotti, M.D. a,b, Cecilia Casetta, M.D. a,b, Valentina Fanti, M.D. a,b, Edoardo G. Ostinelli, M.D.a,b, Rebecca Ranieri, M.D.a,b, Irene Vanelli, Ph.D. c, Armando D’Agostino, Ph.D. a,b,*
a
Department of Health Sciences, Università degli Studi di Milano, Milan, Italy b c
Department of Mental Health, San Paolo Hospital, Milan, Italy Department of Psychiatry, San Raffaele Hospital, Milan, Italy
* Corresponding author at: Department of Mental Health, San Paolo Hospital, Via A. Di Rudinì 8, Milan, Italy; telephone: (+39) 0281844516; fax: (+39) 0281844026; e-mail address: [email protected] (A. D’Agostino).
ABSTRACT Although central to any exhaustive theory of human subjectivity, the relationship between dream and waking consciousness remains uncertain. Some findings suggest that dream consciousness can be influenced by severe disorders of thought content. The suppression of unwanted thoughts has been shown to influence dream content in healthy individuals. In order to better define this phenomenon, we evaluated the persistence of obsessive/compulsive themes across the dream and waking cognition of OCD patients and in a control group of healthy subjects. Participants were administered a shortened version of the Thematic Apperception Test to produce a waking fantasy narration, and were trained to keep a dream diary. Dream and waking narrative contents were analyzed in order to recognize obsessive/compulsive themes, and to calculate Mean Dream Obsession/Compulsion (MDO, MDC) and Mean TAT Obsession/Compulsion (MTO, MTC) parameters. No
differences were found between the two populations in terms of MDO, MDC, MTO, nor MTC. Density of obsessive and compulsive themes were significantly higher in dream reports than in waking narratives for both groups. No correlation was observed between MDO/MDC scores and Y-BOCS obsession/compulsion scores in the OCD group. These findings strengthen the discontinuity hypothesis, suggesting that ruminative aspects of cognition are somehow interrupted during dream activity.
KEYWORDS Dream content; Intrusive thoughts; Obsession; Continuity hypothesis.
1. Introduction Abnormal dream content is seldom considered of clinical utility in contemporary psychiatric practice. However, some studies suggest that abnormal, disorder-specific dreams are reported by most subjects diagnosed with a mental disorder (Beauchemin and Hays, 1995; Sauteraud and Menny, 1997; Schredl and Engelhardt, 2001; Cartwright et al., 2006; Lusignan et al., 2009; Zanasi et al., 2011). Although hypotheses on the relationship between dream and waking experiences have been proposed, results from this field of research remain sparse (Kröner-Borowik et al., 2013). The poor understanding of mechanistic links between psychiatric diagnoses, sleep abnormalities and chronobiological disruptions contributes to the lack of certainty (Wulff et al., 2010). One previous study from our group found that some delusional themes recur within the dreams of acute inpatients diagnosed with
affective and non-affective psychoses (D’Agostino et al., 2013). This finding suggests that severe disorders of thought content may influence the dream experience. Obsessive-Compulsive Disorder (OCD) is a clinical condition in which the hyperactivity of the orbito-frontal cortex (OFC), the anterior cingulate cortex (ACC) and the basal ganglia determines intrusive, distressing thoughts coupled with ritualistic behaviours (Paus, 2001; Whiteside et al., 2004). The study of continuity/discontinuity of obsessive/compulsive contents across wakefulness and dreams in this population yielded inconsistent results (Sauteraud et al., 2001; Kuelz et al., 2010). Whether or not obsessive thoughts persist within patients’ dreams and to which extent remains unclear. Given the peculiar, distressing nature of waking thought in this population, a clarification of its relationship with dream content seems necessary. The main objective of this study was to evaluate the persistence, if there is one, of obsessive/compulsive themes across the dream and waking cognition of OCD patients. Given the paucity of previous findings, we made no specific prediction over the content analysis of dreams in OCD patients.
2. Methods
2.1 Participants All patients diagnosed with Obsessive-Compulsive Disorder (OCD sample) according to DSM-5 criteria (American Psychiatric Association, 2013), who accessed the OCD outpatient clinics of the San Raffaele and San Paolo Hospital in Milan, Italy, were asked to participate. All participants were unpaid volunteers, and informed consent was obtained from all subjects after detailed explanation of the study purpose and
design. 18 subjects were randomly chosen from a previously implemented database of healthy control subjects from the general population (control sample). All relevant demographic data of the experimental samples are reported along with clinical characteristics in Table 1.
OCD sample Control sample p (n=18) (n=18) Male 10 (55%) 9 (50%) n.s. Female 8 (45%) 9 (50%) Age (years) 38.4 ± 11.1 43.6 ± 16.6 n.s. Education (years) 13.4 ± 3.6 14.7 ± 3.5 n.s. Age of onset 18.5 ± 9.3 Y-BOCS total score 28.9 ± 7.5 Y-BOCS obsessions 15.0 ± 3.6 Y-BOCS compulsions 13.9 ± 4.5 HDRS tot score 7.7 ± 4.8 Reported dreams 58 67 Reported fantasies 126 124 SSRI 10 (56%) Fluvoxamine 7 Sertraline 3 Paroxetine 2 SNRI 2 (11%) Duloxetine 1 Venlafaxine 1 TRICYCLIC 5 (28%) Clomipramine 5 SGA 7 (39%) Risperidone 3 Olanzapine 2 Aripiprazole 1 Quetiapine 1 BENZODIAZEPINE 5 (28%) Table 1: Sociodemographic and clinical data of the experimental populations. OCD: Obsessive Compulsive Disorder; Y-BOCS: Yale-Brown Obsessive Compulsive Scale; HDRS: Hamilton Depression Rating Scale.
Exclusion criteria for all participants were a present or past history of serious medical or neurological diseases, sleep disorders, mental retardation, substance
abuse, perinatal injury, or cranial trauma. An additional exclusion criterion for the OCD sample was a present history of depressive symptoms, as confirmed by a Hamilton Depression Scale (HAM-D) score > than 17 in all selected patients. Family history of a major mental disorder was an adjunctive exclusion criterion for the control sample. None of the patients included in the study were drug-naïve. Various combinations of psychotropic agents were administered to all patients during the week in which the experimental material was collected.
2.2 Clinical assessment Clinical diagnoses were confirmed with the Mini-International Neuropsychiatric Interview (M.I.N.I.). Hamilton Depression Rating Scale (HDRS) score < than 17 confirmed the absence of clinically relevant depression in the OCD sample. Clinical assessment was performed using the Yale-Brown Obsessive Compulsive Scale (YBOCS). Available reference values indicate that OCD patients’ clinical condition could be considered severe (Goodman and Price, 1992). The scales were carried out during the week in which patients were asked to keep a dream diary. Y-BOCS analysis of the control group were not performed as the scale was not administered to controls.
2.3 Dream report and waking fantasy collection Participants were trained to keep a dream diary where each morning they reported dreams from the previous night. Subjects who successfully reported at least one dream were then administered a projective test used to elicit waking fantasy stories: the Thematic Apperception Test (TAT) consists of a broad set of figures,
differentiated into groups of 20, according to sex and age. Seven figures were used to elicit the subjects’ projections (1, 3GF/3BM, 6GF/6BM, 9GF/9BM, 12F/12M, 15, 18GF/18BM); a shortened version of the test has been used because the cards were employed as an experimental stimulus to produce stories and not as a standardized projective test (Fiss et al., 1966; D’Agostino et al., 2010; Kramer et al., 2011; Cavallotti et al., 2014). The test was administered in the morning, and the instructions conformed to the standardized TAT procedure (Teglasi, 2001); all waking narratives were taperecorded and then transcribed.
2.4 Scoring procedure Two trained judges (S.C. – R.R.) with experience in administration and elaboration of the Y-BOCS, analyzed the dream material and the waking narratives of the two groups to identify themes from the obsessions and compulsions by using the Y-BOCS checklist. This scoring procedure was performed and reported in a previous study by Sauteraud et al. (2011). Both judges were blind to the authors of the narrative productions and to their diagnoses. First, all narratives were randomly divided and the judges independently scored 125 waking narratives and 62 dream reports each; then each judge checked the other’s scoring and discussed any divergent opinion until a consensus was reached. Obsessive/compulsive themes were quantified as follows:
(i) One point was assigned for each obsessive or compulsive theme identified.
(i) For each subject, the sum of all obsessive themes scored in dreams was divided by the number of available dream reports (Mean Dream Obsession, MDO). The same procedure for compulsive themes yielded a Mean Dream Compulsion (MDC) index.
(i) Following the same procedure, a Mean TAT Obsession (MTO) and a Mean TAT Compulsion (MTC) index was developed for each subject.
2.5 Statistical Analyses A two-way Analysis of Variance (ANOVA) for repeated measures was performed to assess the effect of diagnosis on the average number of words in dream and TAT reports; parametric analyses were chosen given the normal distribution of data. Two one-way ANOVAs were run to independently estimate the effect of the OCD diagnosis on the presence of obsessive and compulsive themes in dreams. A twoway ANCOVA was then performed to estimate the effect of the OCD diagnosis on the amount of obsessive elements identified in the dreams and waking fantasies with the average number of words as a covariate. The same procedure was then used to determine the effect of the OCD diagnosis on the compulsive themes scored. Finally, a bivariate correlation was used within the OCD population to investigate the trend of the content variables in relationship to the psychopathological scores obtained with the Y-BOCS.
3. Results Dreams were found to be on average three times longer than the waking narratives within the OCD population and about two times longer in healthy subjects
[F(1,34)=33.542, p < 0.001]; however, the interaction of average word count per diagnosis was not found to be statistically significant [F(1,34)=4.00, p = n. s.]. Figure 1 shows obsessive/compulsive themes scored in the dreams and waking fantasies of OCD patients and healthy controls. No differences were found between the two populations in terms of Mean Dream Obsession [F(1,34)=0.138, p = n. s.]. Likewise, the two populations were not found to differ significantly in terms of Mean Dream Compulsion [F(1,34)=0.004, p = n. s.]. Furthermore, no statistically significant difference was found between the two populations in terms of Mean TAT Obsession [F(1,32)=0.246, p = n. s.] and Mean TAT Compulsion [F(1,32)=0.448, p = n. s.]. The density of obsessive themes was clearly found to be higher in the dream reports than in the narratives elicited by the TAT tables for both groups [F(1,32)=7.484, p < 0.05]; this effect was correlated to the average word count of the different narratives, which was higher for dreams [F(1,32=7.947, p < 0.01]. The amount of compulsive themes was slightly but significantly higher in the dream reports than in the waking fantasies of both groups [F(1,32)=6.416, p < 0.05], an effect that was found to be independent of the average word count. Within the patient group, no correlation was observed between waking Y-BOCS obsessions/compulsions scores and the number of obsessive/compulsive themes identified in their dream reports.
4. Discussion
4.1 Discontinuity of obsessive/compulsive content across wakefulness and dreams
78% of OCD patients and 83% of healthy control subjects reported at least one dream in which obsessive themes were identified, whereas compulsions and rituals recurred in the dreams of a lower number of subjects (38% of OCD patients and 66% of healthy controls). The intrusive quality of cognition, also belonging to obsessive intrusive thoughts, might be an adaptive aspect of human nature (Salkovskis, 1989; Clark and Purdon, 1995). The lack of differences between the two populations excludes a specific effect of the OCD diagnosis on the amount of obsessive/compulsive themes in dreams. This finding is in line with one previously published study, in which the dreams of OCD patients were not found to differ substantially from those of healthy control subjects (Sauteraud et al. 2001). On the contrary, Kuelz et al. (2010) found a high frequency of compulsive content before inpatient treatment. The absence of correlation between waking Y-BOCS scores and Mean Dream Obsession/Mean Dream Compulsion scores suggests that the pathological repetitiveness observed in wakefulness is somehow interrupted during dream sleep. Taken as a whole, these findings fail to support the continuity hypothesis, according to which dreams reflect waking-life experiences (Domhoff, 1996). The high rate of obsessive/compulsive elements observed in both our samples suggests that such themes could be more characteristic of physiological dreaming than previously thought. Hyperactivity of ACC, OFC and basal ganglia found both in OCD (Paus, 2001; Whiteside et al., 2004) and during REM sleep (Braun et al., 1997; Nofzinger et al., 1997) could justify the presence of obsessive and ritualistic thoughts that were observed in both the elicited waking reports and in the dream diaries. This shared pattern of neuro-functional activation across states raises the possibility of intriguing speculative hypotheses. Indeed, REM dreams have been proposed to
serve a mnemonic function by elaborating and associating waking experiences into vivid images (Llewellyn, 2013; Llewellyn, 2015). Tulving et al. (1996) suggest that novelty (i.e., non-habitual, “off script” activities) determines the extent of elaborative encoding. Therefore, one might speculate that only novel daytime experiences are associated in dreams, whereas OCD behavior is repetitively associative during wakefulness. In this light, some aspects of the disorder might reflect a compensatory mechanism for reduced associative activity during REM sleep dreaming. In terms of sleep architecture, reduced REM sleep latency and increased REM sleep density are also commonly reported in this population. Indeed, one study found that a small subgroup of OCD patients experienced sleep onset REM periods (Kluge et al., 2007). However, one recent meta-analysis (Nota et al., 2015) failed to confirm abnormalities of REM sleep in these subjects and no direct inference from our sample can be done due to the lack of polysomnographic data. Furthermore, the majority of OCD patients were on treatment with drugs that tend to suppress both Slow Wave and REM Sleep (Argyropoulos and Wilson, 2005; Achermann and Borbély, 1987; Borbély et al., 1985; Gaillard and Tissot, 1973). In order to better address the relationship between brain activity and obsessive/compulsive mechanisms during wakefulness and sleep, future studies should investigate sleep architecture and oneiric activity in OCD patients. Indeed, depressed patients have been shown to experience changes in dream contents that reflect their clinical status (Cartwright et al. 1998), which is not known for OCD. Furthermore, the effect of antidepressant drugs on the emotional tone of dream mentation has been investigated (Schredl et al. 2009), although there are no studies on the effect of these drugs on the dreams of OCD patients. In general, Selective Serotonin Reuptake Inhibitors (SSRIs) are thought to intensify dreaming
whereas tricyclic antidepressants increase positive dream emotions (Tribl et al., 2012), two aspects that do not appear relevant to the main findings of our study. Nonetheless, further studies are needed to confirm our preliminary observations in drug-naïve OCD patients. Despite typical recall rates for nighttime dreams (80% and 43% respectively) suggests that dreaming mentations collected in a diary come preferentially from REM phase (Carr & Nielsen, 2015), EEG studies are needed to characterize better the origin; formal differences in form (Noreika et al. 2009) and length (Blagrove et al. 2011) have been investigated.
4.2 Methodological limitations Several limitations should be considered in discussing these preliminary results. First of all, enrolled patients were on treatment with psychoactive drugs which might have influenced several aspects of dreams and waking fantasies. Given the broad variety of drugs administered to patients (SSRIs, tricyclics, benzodiazepines, and mood stabilizers), specific effects could not be studied in comparison to the control group. Antidepressants, antipsychotics, mood stabilizers, anxiolytics and hypnotics are all known to influence several aspects of sleep architecture in highly variable ways (DeMartinis and Winkour, 2007). Second, participants completed their diaries in different sleep conditions. Whereas most OCD patients and all controls reported dreams in a home setting, most acutely psychotic patients were hospitalized at the time of data collection. Indeed, dream recall frequency, length of reports and content variables have been found to vary across experimental settings (Schredl, 2007). Finally, the stages of sleep from which the dreams derive were not investigated.
Reduction of total sleep time, sleep efficiency and subjective sleep quality have been found to recur in OCD patients (Paterson et al., 2013).
4.3 Conclusions In conclusion, the results of this study weigh against the continuity hypothesis, suggesting that sleep somehow interrupts the mental repetitions that phenomenologically define OCD. Although patients affected by the disorder continuously attempt to control their distressing thoughts, these do not appear to emerge in dreams significantly. Further studies are needed to clarify whether obsessive, ritualistic thought processes characterize physiological dreaming.
Acknowledgement
Role of funding sources None.
Contributors A.D’A. and V.F. designed the study and wrote the protocol. C.C. conducted literature searches and provided summaries of previous research studies. I.V. recruited subjects at the San Raffaele Hospital and V.F. recruited subjects at the San Paolo Hospital. S.C. and R.R. administered evaluation scales and performed analysis on the narratives. E.G.O. conducted the statistical analysis. A.D’A. and S.C. co-wrote the first draft of the manuscript and all Authors contributed to and have approved the final manuscript.
Conflict of interest All authors declare that they have no conflicts of interest.
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Figure 1: Obsessive/compulsive themes scored in the dreams and waking fantasies of OCD patients and healthy controls. MDO: Mean Dream Obsession; MDC: Mean Dream Compulsion; MTO: Mean TAT Obsession; MTC: Mean TAT Compulsion.
HIGHLIGHTS Several findings suggest that dream consciousness can be influenced by severe disorders of. thought content. Our findings appear to strengthen the discontinuity hypothesis between dream and wake. experiences. The ruminative aspects of cognition are somehow interrupted during dream activity.