Cognitive Theories of Generalized Anxiety Disorder

GENERALIZED ANXIETY DISORDER

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COGNITIVE THEORIES OF GENERALIZED ANXIETY DISORDER Deane E. Aikins, PhD, and Michelle G. Craske, PhD

This article presents cognitive models of generalized anxiety disorder (GAD) and a critical review of the empiric literature in which GAD has been associated with affect-related information-processing biases, particularly in the domains of attention, memory, and problem solving. Not included in this article are studies of cognitive features of nonclinical anxiety and worry, although this body of research may be relevant to GAD. The core feature of GAD, worry, is regarded as maladaptive information processing, biased in the direction of threat. The centrality of ”threat” to everyday events and possibilities clearly is mirrored in the concerns commonly expressed by individuals with GAD-judging another’s look of disapproval as a sign of personal social failure or judging lateness as a sign of personal incompetence, but despite the flood of research in this area and the robust evidence for certain types of cognitive biases in GAD, the empiric investigation of threat-related information processing is in its infancy. Most paradigms used to date fail to test key assumptions of the cognitive models of GAD. Also, testing of the extent to which affect-related information-processingbiases are unique to GAD or are common to all of the anxiety disorders generally is absent. After reviewing the extant literature, the authors suggest several novel tests of affective information processing and highlight the benefits of using multiple comparison groups and prospective

From the Division of Adult Psychiatry, Department of Psychiatry, University of California, Los Angeles; the Neuropsychiatric Institute and Hospital (DEA); and the Department of Psychology, University of California, Los Angeles (MGC), Los Angeles, California

THE PSYCHIATRIC CLINICS OF NORTH AMERICA

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VOLUME 24 * NUMBER 1 MARCH 2001

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studies to fully test the hypothesis that cognitive biases contribute to the development and maintenance of GAD.

ETIOLOGY AND MAINTENANCE OF GENERALIZED ANXIETY DISORDER

Excessive and uncontrollable worry, accompanied by physical symptoms, such as fatigue and muscle tension, comprise the diagnosis of GAD.2 Although worry is a feature of all anxiety disorders, only in GAD is worry the core feature of the disorder. GAD has been described as pervasive anxiety that is accompanied by an unwanted focus of attention on distressing life topics. In contrast to phobias, in which the unwanted attentional focus is directed largely toward an invariant stimulus (e.g., spiders; snakes; or, in the case of patients with social phobia, negative evaluation), persons with GAD have a transient attentional focus, shifting with the flux of potential future life stressors (e.g., focusing on family concerns during holidays, self-worth concerns during moments of interpersonal intimacy, and career concerns during job interviews). Several information-processing models of GAD implicate worry as the key factor in maintaining GAD.=, Before reviewing the maintenance factors, the causes of worry and GAD are reviewed. Borkovec5 attributed the origins of worry in patients with GAD to a general misperception of future events as negative and catastrophic. One pathway by which danger perceptions may develop is early experience with lack of control and prediction over negative o ~ t c o m e sSome .~ evidence derives from trauma-history research. Content analysis of the types of past trauma reported by subsets of subjects with and without GAD suggests different patterns across groups.65Subjects with GAD reported traumas involving illness, injury, or death at a greater rate than did nonanxious participants, which contrasts with the self-reported worry content from GAD-analogue and patient populations, in whom illnessrelated and injury-related concern was the most uncommon area of worry. The investigators viewed the disparity between trauma history and worry content as evidence for worry as a mechanism for avoiding intense negative affect, discussed later. The notion that negative life events generate a vulnerability to GAD overlooks the possibility that GAD tendencies may have preceded the traumatic event and served as a moderator of the impact of the trauma experience and later reports of it. Also, the potential role of negative life events and resultant danger-laden perceptions is not limited to GAD. For example, prevalence of trauma is elevated in other anxiety disorder^.^^ Theorists suggest that such a perception, or schema, of the world as a dangerous place contributes to elevated judgments of risk and ratings of negative valence that act as a core vulnerability factor for all of the anxiety disorders? What may differentiate GAD from other anxiety

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disorders is the pervasiveness of the worry or the variant focus of GAD worry. Another potential origin for worry and GAD are characteristics of the mother-infant relationship. Bowlby’s9 seminal description of caregiver-infant attachment relationships suggests how qualitative differences in attachment relationship mediate an infant’s emotional regulation. Insecure attachment relationships may be of chief importance to GAD in adults. In a survey of GAD analogues, nonanxious controls and somatically anxious, non-GAD individuals, GAD-analogue respondents rated greater feelings of enmeshment or role reversal and preoccupying anger and oscillating feelings toward the primary ~aregiver.~ Additional measures of attachment (Adult Attachment Interview) with patients with GAD support the insecure-attachment hypothesis.1s Patients with GAD also reported more conflictual feelings regarding their caregivers and lack of childhood memories, which the investigators suggest may be evidence of cognitive avoidance of intense negative affect. Nevertheless, no direct evidence shows that a history of trauma or insecure attachment relationships lead specifically to the development of GAD relative to other anxiety or mood disorders. Additional retrospective analyses of the parent-child relationship suggest that parental overprotection and lack of emotional warmth are factors that may contribute to the later development of anxiety disorders. Parker67hypothesized that parents who exhibit excessive involvement in reducing a child’s possible negative experiences (e.g., overprotection) may limit the child’s ability to independently cope with the environment. Also, parents who are consistently unresponsive (i.e., lack emotional warmth) may contribute to a child’s belief in a lack of personal control over the environment. In a comparison of reports of parenting style among patients with panic disorder, GAD, and matched nonanxious controls, overprotection was associated with panic disorder and GAD, whereas a low level of parental warmth was significantly associated only with panic disorder.” Therefore, although these factors are not unique to GAD, control and warmth may contribute to the later development of pathologic anxiety. Worry may contribute to the persistence of GAD by several pathways. The first concerns the potential for worry to minimize intense negative affect. Patients with GAD describe worrying as a type of verballinguistic rumination about concerns regarding health, finance, and interpersonal relationship~.~~ That is, patients with GAD report that they are overwhelmed by negative outcomes of current life stressors, often expressed as elaborate, catastrophic, “what-if” speculations (e.g., “My supervisor needs to have this report tomorrow; what if it’s not good enough or I can’t finish it on time?” or, “My fianc6 and I have to make a choice between job offers; what if I choose the wrong one?”). Also, patients with GAD rate their mental activity while worrying as involving more thoughts than images compared with nonanxious control^.^ Previous researchs2 suggests that nonanxious individuals experience affectladen material with less autonomic arousal when they use verbal-linguis-

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tic methods similar to those described by patients with GAD (e.g., talking to oneself about a future threat) than when using imagery methods (e.g., visualizing the occurrence of a future threat). Given that worry seems to dampen autonomic arousal, investigators have suggested that worrying is an attempt by patients with GAD to avoid intense affect. By experiencing less intense affect, the process of worry as a coping strategy is reinforced. One implication from this model is that intolerance for negative affect may underlie the tendency to engage in excessive worry, but no direct test of this hypothesis has been performed. Nevertheless, evidence shows that sustained imaginal exposure of aversive scenes results in habituation and eventual reduction in negative affect in patients with posttraumatic stress disorder (PTSD)or obsessive-compulsive disorder.28,29, 71 Therefore, investigators hypothesize that persons with GAD use worry to avoid emotions that are judged too painful to fully experience, resulting in the short-term alleviation of negative affect and associated arousal: but at the same time, the strategy of worrying is counterproductive to long-term habituation and reduction in negative affect, thus perpetuating the maladaptive state of anxiety and worry. A second pathway by which GAD is maintained involves the content of worry. Worry is often about future threat for which the likelihood of occurrence is low (e.g., being fired, evicted, or ostracized), which creates the paradoxic situation of no proximal threat from which to escape or to attack. This lack of a behavioral solution (e.g.! escape or attack) is hypothesized to prompt continued rumination and worry? Third, to the extent that an individual believes that worry has assisted in successfully avoiding a negative situation, excessive worry is prolonged through negative reinforcement.6 For example, beliefs that worrying about harm coming to a child during a school trip prevented harm from happening, or, conversely, that to not worry places a child at greater risk for harm, increase the likelihood of worrying. Additional beliefs about the negative consequences of worry (e.g., "Worry could make me go crazy"; "Worrying is abnormal.") may cause worrying about worry and contribute to its excessiveness. Distress over excessive worry may lead to attempts to suppress worry! which only increases the prominence of worry-related activity. Failures to suppress worry then 84 Interestingly, may confirm beliefs concerning the dangers of when asked about positive and negative beliefs regarding worry! small samples of patients with GAD were indistinguishable from other patient populations, including patients with obsessive-compulsive disorder.I7 Therefore, the degree to which distorted beliefs regarding the value of worry are pathognomonic of GAD has yet to be established clearly. In summary, threat-related schema, possibly arising from unpredictable or uncontrollable negative life events, or parent-child relationships among other things, may be a vulnerability factor for excessive worry and GAD and other anxiety disorders. Unique to GAD or to pervasive worry over invariant possibilities may be the use of worry about distal threat, for which no appropriate action exists, to alleviate intense

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tive affect, which, in turn, generates a self-perpetuating cycle of uncontrollable worry. Next, the nature of the information-processing biases that produce or are produced by the state of worry in GAD is considered. AFFECTIVE INFORMATION PROCESSING BIASES IN WORRY

Worry in people with GAD has been hypothesized to be associated with an increased sensitivity to threat-related external cues (i.e., attentional bias), negative interpretations of ambiguous stimuli, facilitated activation of threat-related memory, and deficits in problem solving.25,45 These cognitive-processing biases are believed to result from a state of worry and to enhance the state of worry, leading to a self-perpetuating cycle. Attentional Bias

Worry has been hypothesized to bias attention toward threat-related information for patients with GAD by various cognitive mechanisms. One such mechanism is using strategic or controlled attention in favor of threat-related stimuli, whereas non-GAD controls are predicted to divert attention away from threat-related ~timuli.2~ This process is referred to as selectivity of attention and is evident in the distress that people with GAD have over threat-related information even when it is embedded within positive information (e.g., “Yes, my boss said the report was good, but some corrections were needed and I worried about what would happen if I didn’t fix them to her satisfaction.”). Support for selective biases for threat-related information in people with GAD originated with the use of the dot-probe task. This paradigm involved briefly presenting threat-related and neutral valence words on a display screen. At intervals unknown to the participants, one of the words was replaced with a target ”dot,” requiring a response. Individuals with GAD have been shown to respond faster to the target dot when it follows a social or physical threat-related word relative to nonanxious controls.43, Despite a methodologic criticism that the original paradigm confounded the probability of target occurrence with threat-related words, later modified studies continued to demonstrate support for the selective attention bias in people with GAD.59Anxious children also show a bias for threat-related words, although nonanxious children seem to differ from nonanxious adults by failing to demonstrate bias away from threat-related information.a1 Another paradigm for testing selective attentional processing is the lexical decision task. Individual letters are presented briefly, and participants judge whether they constitute a real word. Persons with GAD have demonstrated faster decision-making times for threat-related over non-threat-related words relative to Early methodologic

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criticisms that participants would demonstrate faster decision-making times for semantically related over nonrelated words were successfully addressed by subsequent investigations comparing words from different categories (threat versus household items); persons with GAD shifted attention to threat-related words.62People with GAD also may demonstrate selective biases toward pictures of affective facial expressions,'2 but preliminary results indicated that adults with GAD *showedselectivity for positive and negative faces relative to neutral expressions. Therefore, further research is needed to clarify potential affective biases with nonlexical stimuli. Selective attention has been hypothesized to differentiate people with GAD and nonanxious individuals only when presented with stimuli that are considered to be relatively minor threats, such as words.26In the presence of a more prominent threat, both populations are predicted to attend to the stimuli. This prediction derives from the theoretic assumption that the syndrome of GAD is not qualitatively different from anxiety in the general population and that, instead, persons with GAD position at the extreme end of a continuum of readiness to perceive threat, such that minor threats are defined as major threats. Additional research is needed to address this important issue. Disruptions in attentional processing for persons with GAD have been conceptualized as "uncontrollable" distractions from negative or threat-related stimuli, which represents attentional interference effects and is clinically evident in difficulty concentrating on non-worry-related thoughts when worry-related thoughts are present (e.g., "I started to read my book, but the clock ticking reminded me that my daughter was out, and I worried about her getting home safely. I never finished the page."). The dichotic listening paradigm targets this attentional feature by requiring participants to verbally repeat ("shadow") nonthreatening information being played into one ear through headphones. Although participants are engaged in this task, threat-related and non-threatrelated words are presented to the other ear. People with GAD exhibited more disruptions of their shadowing task when threat-related as opposed to non-threat-related words were presented in the nonshadow Also, people with GAD showed increased distractibiliV8 or slower visual search times when threat-related distractors were present.49 A classic paradigm of attentional interference is the Stroop test.77 Participants are shown lists of color names (e.g., red) printed in different colored inks (e.g., blue) and told to read aloud the color of the ink versus the word. The colored words create a distraction in attention, causing errors and delays. This test has been modified for use with clinical populations by comparing the interference effects of anxietyrelated and non-anxiety-related words printed in colored inks. A modified Stroop effect has been found among people with GAD for threatrelated words.46The interference effects of the Stroop test may be content specific; patients with GAD categorized by their somatic or social performance concerns exhibited Stroop effects only in relation to their concerns.64

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Attentional disruptions also involve automatic or noneffortful processing biases toward threat-related information that preclude strategic uses of attention. The clinical result is to notice anxiety and heightened vigilance without conscious perception of threat. In accord, persons with GAD continue to show Stroop interference effects even when stimulus words are followed by screens, preventing their verbal identificati0n.l' Groups with GAD also exhibit bias to subliminal presentation of threatrelated words in the dot-probe Some investigators consider threatrelated biases for subliminal information as evidence for a "preattentive" or "preconscious" bias in GAD, but the methodologic criteria necessary to demonstrate automatic and preattentive processing is debatable despite the current vogue of the term.37M ~ N a l l ynoted ~ ~ that several aspects of the paradigms used clearly do not meet the criteria for automatic processing. Such subliminal attentional biases may be better considered as preverbal rather than automatic or preattentive pro~essing.2~ Cognitive models of attentional biases in GAD have integrated psychophysiologic measures of information processing. Worry states and GAD have been related to one particular mechanism of the parasympathetic branch of the autonomic nervous system: vagal tone in cardiovascular activity. The vagus nerve is responsible for slowing the heart rate and maintaining a homeostatic e n ~ i r o n m e n tNatural .~~ decreases in vagal tone, mostly indicative of increases in sympathetic activation, have been found to occur during states of cognitive activity (e.g., mental math) and muscle tension.33,34 In contrast, increases in vagal tone have been associated with states of relaxation. Most importantly, these variations in vagal tone are suggested to affect attentional processing. That is, increases in vagal tone, measured as longer interbeat intervals (IBIs), have been characterized as orienting responses toward external stimuli, whereas decreases in vagal tone, measured as shorter IBIs, are characterized as minimizing attention to external events, possibly to facilitate internal thinking.69Populations with a deficiency in vagal tone (e.g., children with attention-deficit hyperactivity disorder) have increased di~tractibility.~~ ShGrter IBIs (i.e., low vagal tone) seem to be characteristic of worry and of GAD. Cardiovascular reactivity of GAD analogues and controls was measured during relaxation and worry sessions. For control participants, aversive imagery and worry conditions reduced vagal tone relative to nonaversive imagery and relaxation conditions. In contrast, subjects with GAD demonstrated no differences in vagal tone to the experimental conditions, rather demonstrating consistent decreased vagal tone compared with These findings suggest not only that worry reduces vagal tone but that people with GAD, being in a fairly constant state of worry, show a pervasive profile of reduced vagal tone. In a manner similar to the GAD analogues, Patients with GAD in another study had shorter IBIs and lower high-frequency spectral power (another index of vagal parasympathetic activity) in both conditions relative to nonanxious controls.79Also, subjects with GAD had greater autonomic restriction, with less variability in vagal tone activity. The

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investigators suggest that this feature of inflexibility in vagal-tone responsiveness may be related to inflexibility of cognitive-processing biases or result from a general elevated state of preparedness for threat. These studies are limited to conditions of worry versus nonworry, however, and do not test psychophysiologic responsiveness directly in relation to attentional processing. One indirect study of arousal and attention examined the degree to which negative performance feedback acted as an attentional distracter and generated increased muscle tension.22Contrary to expectations, subjects with GAD showed poorer performance with the neutral compared with negative performance feedback. Also, measures of psychophysiologic arousal were not significantly different from nonanxious controls despite GAD participants' elevated self-reported levels of worry during the negative-feedback condition. To explain the lack of findings in the group with GAD, the investigators suggest that increased arousal may be necessary for attentional-processing disruption, and elevated arousal was not achieved in this study. Clearly, the role of physiologic arousal in cognitive processing has not been determined. Additional research is required to examine the degree to which a parasympathetic deficit in people with GAD influences processing of threat-related and non-threat-related stimuli.

Threat-Related Interpretations of Ambiguity

Another domain of information processing in GAD is threat-related interpretations of ambiguous stimuli. Patients with GAD often worry about catastrophic consequences from unclear situations (e.g., "When my friend didn't say anything about the lunch I made, I started worrying that I had really done a bad job preparing it."). Researchers have hypothesized that individuals with GAD select threat-related interpretations of stimuli or generate threat-related interpretations when the contexts are ambiguous.16Support has been generated from tests using homophone^^^ and word selection after ambiguous sentence but these paradigms have been criticized on the grounds that the results are more likely caused by the experimenter demand characteristics and responseselection bias effects.**In other words, the leap to catastrophic consequences from ambiguous situations may simply reflect habit or selfdefinition (e.g., "I always jump to the worst conclusion, and, therefore, I will assume the worst conclusion in this situation too because that is who I am.") rather than an active interpretation bias. Covert reading comprehension may provide a better test of interpretation bias. In this paradigm, differences in reaction-time responses to ambiguous sentences are measured. Preliminary results seem promising, as high trait anxious individuals demonstrated longer reaction times to ambiguous sentences that had a possible threat-related interpretation compared with low trait anxious To date, however, no studies using this paradigm have been conducted with GAD popula-

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tions, so conclusions regarding interpretations of ambiguity are equivocal. Memory Bias Although selective attentional bias and attentional interference for negative-valenced words have been demonstrated consistently, memory processes in patients with GAD are less clearly understood. Most of the memory research derives from Bower’ss model of mood-congruent memory, referring to the degree to which a positive or negative mood state facilitates memory for semantic information of similar valence and inhibits information of dissimilar valence. In this model, information regarding emotions is organized into mood schemas, or categorized hierarchies of emotionally related information. The degree to which an affective word is semantically related to a mood category is represented in the model as the proximity of the word in the hierarchy. Because of the relative hierarchic positioning of linguistic nodes within a schema, Bower predicted that, during a memory test, an individual in a negative mood would have facilitated recall of negative words and inhibited recall of positive words. As applied to populations with GAD, a global perspective of the world as a threatening place may result in the development of a threat schema that renders threat-related information more accessible during states of worry. mat hew^^^ suggested that this activated threat schema would correspond to facilitation of threat-related memories. Evidence for mood-congruent memory effects within the anxiety disorders is mixed, however.55This finding contrasts with more robust findings for facilitated recall of negative material and diminished recall of positive material in depressed groups relative to nondepressed cont r o l ~ . ~ ~52, In the case of GAD specifically, EysenckZ5reviewed negative findings from four of five studies examining recall and recognition biases for threat-related versus non-threat-related material for groups with GAD and nonanxious control groups. Also, findings of a free-recall bias for threat-related words in GAD60 have been criticized on the grounds that the supposed memory bias was more indicative of greater responsiveness to threat-related stimuli than a recall bias for the participants with GAD.55That is, because of the methodologic limitations inherent in free-recall tests, whether groups with GAD encoded more threat-related stimuli than non-threat-related stimuli or whether they simply had a response bias toward threat-related stimuli could not be determined. In other studies, no recall bias for threat-related words relative to positive valence words were found for GAD.50Also, comparisons of groups with GAD to nonanxious controls found no support for mood-congruent memory.59A recognition-memory paradigm also indicated no bias for threat-related words in subjects with GAD.44To complicate matters further, another study even found a recall bias for threat in a nonanxious control group l4rU,

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The previous studies tested explicit memory or effortful attempts to recall. Another type of explicit memory that may be clinically relevant is autobiographical memory. In one study, subjects with GAD did not recall more threatening memories but responded faster and provided more memories when queried about anxious events relative to nonanxious events.15 As with the previous memory studies, unclear with this method of inquiry is whether groups with GAD recall more negative events or interpret more events in a negative manner. In contrast to explicit memory, implicit memory is learning for skills and information that does not require conscious encoding.32Cognitive neuropsychologists suggest that implicit memory is separable from explicit memory systems because particular neurologic patient populations demonstrate intact implicit memory despite impaired explicit memory ~apabi1ii-y.~~ The clinical implication of implicit memory for GAD is that threat-related information may be encoded more extensively than non-threat-related information and later affect cognitive functioning without conscious effort. Implicit memory paradigms for words typically involve presentation of stimuli with some task ulterior to learning (ranging from reading the words aloud to making judgments regarding the words). Later, the participant is asked to complete a word task (i.e., a stem-completion or perceptual-identification test) that includes the words previously seen and novel stimuli. The degree to which the previously seen words affect performance on the word task is considered a measure of implicit memory.31To date, preliminary evidence exists for an implicit memory bias for threat-related words in GAD using a perceptual-identification test,44 although this has not been replicated using a stem-completion test.50,66, 49 These findings should be considered tentative because salient methodologic issues regarding the compatibility of the study and test tasks used by these researchers have not been addres~ed.5~. 72 Additional research that successfully deals with this compatibility issue is warranted before further conclusions regarding implicit memory and GAD may be drawn. In light of the equivocal findings for memory and GAD, some theorists have suggested that individuals with GAD are biased to attend to negative material and then avoid further encoding into memory.63This hypothesis derives from a distinction between the processes required to activate a mental representation of a word and those required to elaboActivation has been described as an rate on the meaning of a automatic process in which exposure to a word results in the facilitation of previously associated words. This activation process requires attentional resources and has been found to be sufficient for encoding a word into implicit memory but not necessarily explicit memory. Elaboru tion has been described as a strategic process in which exposure to a word facilitates new associations with additional words. Elaboration is considered necessary for encoding information into explicit as opposed to implicit memory. In reference to GAD, attentional biases for threat have been hypothesized to occur during the activation stage of word proc e ~ s i n gSimilar . ~ ~ to Bower's spreading activation model, the investiga-

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tors suggest that, when individuals with GAD are exposed to threatening stimuli, additional fear-related associations become automatically activated and further attentional resources are allocated for this processing stage, but additional processing in the elaboration stage is avoided. Therefore, according to this model, individuals with GAD are more likely to demonstrate threat biases for attention and implicit memory, which are more related to the activation-processing stage and are less likely to demonstrate a threat bias in explicit memory because it is more related to the elaboration-processing stage. Teleologic formulations reach a similar conclusion: the purpose of anxiety is to identify potentially threatening stimuli rapidly rather than reflect on past events.56Also, a primary function of biased encoding of threat information may be to facilitate retrieval of behavioral response templates for when the same or similar threats are re-encountered in the future. If, as Borkovec5proposes, motor responses are blocked in persons with GAD because the worry is about distal as opposed to imminent threat, then memory biases are of limited value. Perhaps for this reason, memory biases are more apparent in anxiety groups for whom threat is much more proximal, such as PTSD,25 but although these clinical and teleologic models fit most attention and memory findings in GAD, Williams et alB5did not specify how processing during the automaticactivation stage could discriminate threat-related from non-threatrelated information to determine whether the later elaboration stage is to be avoided, nor could their model explain the inconsistent results of previous studies.55Also, a test of attentional and memory processing in which the elaboration hypothesis was directly tested failed to support the model, thus leaving the relationship between attention and memory bias for GAD largely unre~olved.'~ Problem Solving

Worriers may have higher evidence requirements for making decis i o n ~ That . ~ ~ is, when faced with uncertain threat or an ambiguous situation, patients with GAD may require more time for decision making (e.g., "I may go back and forth over what I should do about anything-my job, my boyfriend, how to approach my colleague without offending her. I may second-guess any decision.") Induced worry results in longer response times in concept-categorization and stimulus-categorization tasks, at least when the tasks are a m b i g u o ~ s . ~ One ~ , sugges~~,~~ tion for these delays is that persons with GAD have higher needs for perfectionism and thus have elevated evidence requirements.68Another suggestion is that they have difficulty tolerating uncertainty, which leads them to consider ambiguous events as dangerous, which, in turn, impedes problem-solving No tests for either hypothesis have been performed. A third possibility is that lack of confidence in cognitive ability may be more significant than deficits in problem-solving skills. In accord,

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GAD-analogue participants self-rated their attention, memory, and cognitive flexibility as impaired, but performance on neuropsychological measures of these abilities was within normal limits and not significantly different from that of nonanxious controls.' Measures of high trait anxiety and worry are related to a lack of confidence in problem solving and avoidance coping.1g,2o Also, when subjects were given negative feedback regarding their solutions to real-life problem situations, they were more likely to develop increased anxiety and catastrophizing worries compared with participants who were given positive feedback.21Davey et a12' hypothesized a two-stage model of information-processing bias in GAD in which negative affect facilitates the recall of catastrophic possible outcomes stored in memory. Then, low confidence in problem-solving skills decreases the ability to successfully rule out many of these catastrophic possibilities as being unlikely, but given that extant research does not show a consistent potentiation of memory for threat-related events, additional research is required to directly test the way in which GAD populations generate threat-related outcomes to possible life stressors. Nevertheless, further analysis of GAD perception of informationprocessing abilities and self-efficacy may help to delineate some of the inconsistent results found in information-processing paradigms. SUMMARY

Patients with GAD seem to be characterized by worry-related biases in attention, possibly in implicit memory, and problem-solving ability or confidence. Specifically, individuals with GAD display selective attentional biases when presented with threat-related information. Autonomic functioning in the type of lowered vagal tone may contribute to these attentional-processing biases. Although people with GAD do not seem to have a processing bias for threat-related, explicit memories, they may exhibit biases for threat-related information in implicit memory. Patients with GAD display difficulty with decision making when faced with ambiguous information. Investigators believe that such affective information-processing biases are related to excessive worry and maintain a reciprocating and self-perpetuating cycle of worry, cognitive biases, and additional worry in GAD, but several methodologic, theoretic, and clinical issues limit strong inferences regarding the causal relationships between such information-processing biases, worry, and GAD. Research Limitations

A major consideration in interpreting the aforementioned cognitive biases for GAD is assessing their discriminant validity. They have been demonstrated in most anxiety disorders: high trait anxious individuals, people with social or specific phobia, and patients with panic disorder or PTSD have all demonstrated selective attentional biases.= Attentional

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interference effects with the modified Stroop test have been found with phobias, PTSD, and panic disorder.25,53 Also, reductions in vagal tone have been observed in people with obsessive-compulsive disorder or panic disorder.35,36 Therefore, affective information-processing biases are not uniquely related to pathologic worry in people with GAD. A discriminating feature of information processing in people with GAD may be the larger domains of content in which the attentional and implicitmemory biases may be generated. In contrast to the more circumscribed attentional and implicit-memory biases in other anxiety groups, the broader content domain for patients with GAD may be related to their variant attentional focus. Thus, cognitive biases may be related to negative affect overall, differing among anxiety disorders only in terms of the content domain. Clinicians await the study of multiple comparison groups, including those with other anxiety disorders and mood disorders, to explore these possibilities further. Future Directions

More direct testing of the cognitive models of GAD involves investigation of the interaction of negative affect, arousal, and cognitive processing. The relationship between vagal tone and attentional processing of threat-related cues has been examined only indirectly. A more direct test requires paradigms in which the degree of bias in attentional processing of threat-related information may be measured in concert with variation in vagal tone under differing levels of affective intensity. One example might be to measure cardiac functioning in response to threatrelated versus non-threat-related stimuli presented in the dot-probe paradigm under conditions of high and low arousal. Another example is to induce a shift in vagal tone and examine the effects on attentional processing. The model proposed by Williams et alS5for initial attention to threatening stimuli followed by diversion to avoid elaboration of processing might be examined electronically by using eye tracking and cardiovascular monitoring. Also, paradigms involving a hierarchy of stimulus-threat intensity could be used to examine cognitive biases in relation to minor threats versus major threats and thus assess GADrelated differences in sensitivity to threat-related cues. From a clinical perspective, many of the features of cognitive processing discussed in this article fail to tap into the most directly observable phenomena of patients with GAD: extreme distress over excessive and uncontrollable worry regarding multiple concerns. Clearly, the paradigms used to date, most of which have involved responding to lists of words, have limited external validity. Perhaps the most directly relevant findings have come from paradigms used by B0rkovec,7~who have elucidated psychophysiologic and worry style features of GAD with instructions for patients to worry ”in the way he/she usually worried.”s0 As suggested by Borkovec, people with GAD use a verbal-linguistic type of worry. Yet, in daily activities, individuals with GAD are con-

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fronted with visual stimuli as they search for threat-related information (e.g., reading facial expressions or looking at a clock and being reminded of a deadline). Visual processing is considered to be separate from lexical processing,3 and visual stimuli may be more strongly related to affective responses than lexical stim~li.3~ Thus, the incorporation of threat-related and non-threat-related oriented pictures in attention and memory paradigms may provide a more ecologically valid and more sensitive test of affective bias in information processing. For example, attention and memory processes could be measured in relation to videotaped positive and negative mock interpersonal interactions. Some evidence shows that disruptions in attentional processing are reversible after successful treatment of For example, GAD performance on attentional tasks improved after cognitive-behavioral but this conclusion was based on comparisons between the GAD and nonanxious groups after treatment. The GAD improvement from pretreatment to post-treatment was not significant, suggesting a limited magnitude of change in attentional biases, but in another study, treatment effects also seemed to impact preverbal attentional pro~ e s s i n gUnfortunately, .~~ sample sizes were small (less then 10 at 20month follow-up) and there was no nonanxious comparison group for the follow-up assessment. Nevertheless, these findings potentially are important for understanding information-processing biases in GAD.In the presence of a danger-laden schema that underlies and generates information processing biases, preverbal tasks would be expected to continue to elicit threat-related biases even after successful treatment. The improvement of performance on preverbal tasks draws into question the notion of a danger-laden schema vulnerability, or, at the least, implies that the effects of such a schema are dependent on elevated state arousal. Interestingly, however, improvement of preverbal attentional processing in the study by Mogg et al.57was largely uncorrelated with most measures of anxiety, save for the reduction of anxiety-related thoughts. Perhaps, then, the relation between affective information-processing, worry, and GAD is better characterized as an indirect model. That is, information-processingbiases may generate worry states by contributing to anxious thinking styles. When combined with negative affect and associated arousal, worry contributes to the development of GAD.Thus, affective information-processing biases per se do not directly lead to GAD.Therefore, amelioration of these biases would not be expected to directly affect GAD.Further research which incorporates measures of attentional, implicit memory, and problem-solving abilities in pre- and post-treatment designs would better elucidate the relation between information-processing, worry, and GAD. In conclusion, patients with GAD and other anxiety disorders have been found to display several information-processingbiases. The degree in which worry is the causal factor in the production of these biases is to be determined. A stronger test of the hypotheses regarding GAD and affective information processing biases would need to incorporate the theoretical, methodological, and clinical factors considered above. These

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would include using comparison groups for tests of discriminant validity and more direct tests of the theoretic assumptions in which models of GAD have been built to better understand the unique factors which lead to affective processing biases for this population. References 1. Aikins DE, Hazlett-Stevens HJ, Degen L, et a1 A neuropsychological screening of

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