THE RELATIONSHIP BETWEEN DSM-III-R-DEFINED OAD AND DSM-IV-DEFINED GAD
Since subsuming the DSM-III-R OAD diagnosis within the DSM-IV GAD diagnosis, clinical and epidemiological studies have provided conflicting evidence about the overlap of the two diagnoses. Kendall and Warman27 in a referred clinical sample using the Anxiety Disorders Interview Schedule (ADIS) Child version (N=40; M=11.13 yrs) reported that there was 98% agreement on parental reports and 93% agreement on children's self-reports of the DSM-III-R-defined OAD and DSM-IV-defined GAD. Tracey et al.28 showed that all children attending a specialist anxiety clinic with a clinical level diagnosis of DSM-III-R OAD would also satisfy criteria for DSM-IV GAD when a diagnosis is based on the aggregate of parent and child reports of symptoms (i.e. using the “or” rule) on the ADIS for DSM-IV, Lifetime version (ADIS-IV-L) (N=62; M=12.8; SD=3.18). There was also complete diagnostic overlap between children with GAD and those with OAD. Epidemiological data, however, show discrepancies between the two diagnoses. In the Great Smoky Mountain Study (GSMS), which uses the Child and Adolescent Psychiatric Assessment and the “or” rule for assigning a diagnosis, Costello et al.29 report that by age 16 182 children (11.6% of sample) had either DSM-III-R-defined OAD, DSM-IV-defined MDD, and/or GAD. However, only 23.5% of those with GAD or OAD had the disorders concurrently. Children who meet OAD or GAD diagnostic criteria may also have different longitudinal trajectories. Bittner et al.30 in the GSMS report that childhood OAD predicts adolescent OAD, panic attacks, and DSM-IV-defined MDD and conduct disorder, whereas childhood GAD only predicted, unexpectedly, adolescent conduct disorder. It is noteworthy that in this study only 14% of cases with OAD also satisfied childhood GAD criteria and that there were no associations between childhood OAD and adolescent GAD and vice versa. Although Pine et al.31 in their prospective longitudinal epidemiological study did not directly compare OAD and GAD, their reports are consistent with Bittner et al. showing that adolescent OAD predicted a range of adult psychopathological outcomes (social phobia, MDD, panic and GAD). In contrast to the Bittner et al.'s study that overall used a younger sample, Pine et al. found adolescent OAD to be related to adult GAD.
DSM-IV-defined GAD in youth has fair to excellent test–retest reliability depending on which informant and which interview are used.32–34 Similar to other childhood disorders the diagnostic agreement between informants (i.e., parent and child) ranges from poor to fair, although symptom-level agreement is typically better.28, 35–37 Few data had accumulated on DSM-III-R-defined OAD before it was incorporated within DSM-IV-defined GAD,38 and there has been limited investigation of the diagnostic thresholds of DSM-IV-defined GAD in youth. Thus, this review at times makes necessary generalizations from adult studies to children. This is a limitation.
In summary, it appears that there is some degree of relatedness between OAD and GAD; nonetheless, more research is needed on whether the DSM-III-R criteria for OAD and the DSM-IV criteria for youth with GAD are identifying the same disorder. Subsequent reference to children and adolescents will thus focus on DSM-IV-defined GAD (as DSM-IV does not include OAD).
DSM-IV CRITERION A: THE NATURE, FOCUS, AND DURATION OF ANXIETY AND WORRY
Anxiety and worry (apprehensive expectation) about a number of future events or activities were introduced as the hallmark features of GAD in DSM-III-R, with the result that GAD was no longer a residual diagnosis.20, 39–41 Worry is the cognitive component, as distinct from the physiological symptoms, of anxiety. There appears to be consensus that worry is an avoidant coping strategy that is negatively enforced by reductions in patients' worry. This reduces emotional reactivity in the short term but because patients do not process their distress other than in the abstract they experience ongoing distress and continue to use worry to reduce this distress.42–47 The concept of cognitive avoidance derives from Borkovec's early work on the nature of worry, suggesting that the worries experienced by GAD patients are predominantly verbal-linguistic rather than imagery based48, 49 and that verbally based cognitions are associated with less arousal when experiencing threatening cues than are imagery-based cognitions.49–51 The hypothesized function of GAD patients' verbally based cognitions is to minimize the autonomic arousal they would otherwise experience if threatening stimuli were processed in imagery.52, 53
Borkovec proposes that these avoidant strategies are implicit, whereas others purport that worrying can be an explicit coping mechanism,43, 47 including the catastrophic “what ifs…?” that are commonly seen when treating GAD. Active suppression of worries, substitution of neutral or positive thoughts for worries, use of distraction techniques to interrupt their worries, and the active avoidance of situations that cause distress are also thought to be strategies used by GAD patients.44, 47 Cognitive avoidance does show some symptom specificity in adults with clinical worry when compared to panic symptoms54 and also decreases with effective CBT treatment.55, 56 In children and adolescents there has been little investigation into the use of avoidant strategies but Gosselin et al.57 did show that nonclinical adolescents who experience high worry (N=158, Penn State Worry Questionnaire (PSWQ) M(SD)=61.2(6.2)) engage in more cognitive avoidance strategies than those experiencing moderate worry (N=187, PSWQ M(SD)=43.8(2.1)). Avoidant strategies significantly predicted worry level, with avoidance of triggers, thought substitution, distraction, and thought suppression accounting for 19% of the variance in the youths' worry scores. Positive beliefs about worry explained a similar amount of variance (14%) as these avoidant strategies.
If clinical and research evidence support retaining a specific component of anxiety—worry when it is focused on multiple events or activities (discussed below)—as the defining feature of GAD in DSM-V, should the disorder be renamed to more clearly convey this central concept of worry? Options include names like “generalized worry disorder,” “major worry disorder,” or “pathological worry disorder.” Indeed, the prominence of worry in this disorder has led GAD patients to often be referred to as “pathological” or “chronic” worriers. The term pathological is used here in the sense that it distinguishes normal and disordered states, but worry is not specific to GAD. People with other anxiety disorders, mood disorders, and no disorders at all, also worry. Thus, how worry is identified clinically, how it is formally defined, and the nature of its associated features will influence the reliability and validity of the revised classification. DSM-IV GAD criteria presume that defining worry as excessive, generalized to multiple activities or events, difficult-to-control, and chronic and disabling, establishes nosological boundaries that identify a reliable, valid, and clinically significant disorder. Evidence for each part of this definition is examined below.
Anxiety and worry that is excessive
Would changing the excessiveness criterion improve the psychometric properties of the GAD diagnosis? Pathological worry defined in terms of “excessiveness” may reduce the reliability and validity of the diagnosis. Excessiveness is an ambiguous term, and as Ruscio et al.58 noted there is no guidance on “what makes worry excessive?” and “who [should] determine if the worry is excessive?” Wittchen et al.59 used the University of Michigan Composite International Diagnostic Interview (UM-CIDI) structured interview in a clinical reappraisal of a subset of National Comorbidity Survey participants who endorsed all criteria for lifetime DSM-III-R GAD (N=24) and those who reported 6 months or more in which they felt worried, tense, or anxious but did not satisfy all the other GAD criteria (N=12). They found that 70% of those who endorsed all GAD symptoms did so at follow up and 58% of those who did not endorse all GAD symptoms again received a negative GAD diagnosis, corresponding to a κ of .53. However, if “unrealistic or excessive” worry was not required for a positive GAD diagnosis, this κ increased to .78. In the same study, excessive or unrealistic worry was also a primary source of discrepancy between GAD diagnoses based on the UM-CIDI and the SCID.59 In their reliability assessment of DSM-IV GAD using the ADIS-IV-L, Brown et al.13 reported that a dimensional measure of excessiveness would be more reliable than the current categorical criterion. In terms of validity, Ruscio60 reported that excessive and uncontrollable worry may be associated with severe worry rather than with GAD per se. Slade and Andrews61 in their cross-classification study reported that although there is 98% agreement between DSM-IV and ICD-10 on negative GAD diagnoses, the two systems only agree on 41% of positive diagnoses. Seventy-two percent of those who endorsed all ICD criteria (including “prominent” worry) did not report excessive worry. This was the largest source of discrepancy between the two classifications.
If the excessiveness criterion were omitted from the GAD definition in DSM-V, the classification would continue to identify a group that experiences clinically significant distress or impairment as measured by endorsement of criterion E. However, the identified group would experience milder symptoms than if they were diagnosed by DSM-IV criteria (Australian National Survey of Mental Health and Well-Being 1997 (NSMHWB-1); National Comorbidity Survey–Replication (NCS-R)).58, 61 This broader classification (i.e., including respondents who report either excessive or nonexcessive worry as having GAD) would also increase the number of children and adults with GAD by approximately 27 to 40% (NCS-R; Early Developmental Stages of Psychopathology (EDSP)).58, 62 For example, in the NCS-R 12-month GAD would increase from 2.0 to 2.8%.
Although omitting the excessiveness criterion may increase the population that would satisfy the remaining GAD criteria, it would not substantially change the type of person identified as having GAD. People with excessive and nonexcessive worry who meet all other GAD criteria are similar in terms of socio-demographics (NCS-R),58 distribution of severity scores (constructed from indices of uncontrollability, impairment, and distress) (NCS-R),58 treatment seeking (EDSP),62 and familiality (NCS-R).58, 62 Furthermore, the variously defined GAD groups have substantial lifetime comorbidity, although for some disorders GAD with “excessive” in the criteria set has significantly higher comorbidity odds ratios than GAD without this term in its criteria set (NCS-R; EDSP).58, 62 GAD that includes “excessive” also begins earlier in life and is more persistent than nonexcessive GAD (NCS-R).58 Interestingly, excessiveness does not clarify the diagnostic border with MDD, perhaps the most challenging boundary condition for GAD, in either the NCS-R or the EDSP (e.g., 12-month MDD is significantly associated with excessive and nonexcessive GAD).58, 62
DSM-V OPTIONS FOR THE EXCESSIVENESS REQUIREMENT
Anxiety and worry (apprehensive expectation) focused on multiple future activities or events that is extreme or disproportionate to those events is the defining feature of GAD and distinguishes GAD from normal worry and other anxiety and mood disorders. Although the excessiveness descriptor reflects the status quo there are no data or clinical consensus in the literature that support identifying another aspect as the core feature of the diagnosis. The data accumulated since the publication of DSM-IV shows that, although omitting the excessiveness requirement from DSM-V would identify people with similar characteristics to DSM-IV in terms of socio-demographics and comorbidity, it would increase the prevalence of the disorder substantially (at least in community samples), and it would identify a milder form of the disorder. Although excessiveness is the largest source of discrepancy between DSM-IV and prominent worry in ICD-10, this is not a problem with DSM-IV GAD per se.
There is limited evidence that removing the excessiveness criterion would increase reliability. Due to its traditional connection with GAD, it may be of more benefit to the classification if further guidance is given as to what excessive means and who (i.e., the patient, a significant other, the clinician) is to determine whether the worry is excessive. “Excessiveness” could, of course, be operationalized by observable outcomes (i.e. amount of time per day spent worrying; degree of interference with concentration on nonworry tasks; behaviors connected with the worry such as checking) as is currently done for symptoms of other emotional disorders such as MDD and obsessive–compulsive disorder (OCD).
Anxiety and worry about a number of events or activities
Adults experiencing GAD worry more pervasively, and about more future events and activities, than adults without GAD, and they tend to worry more about interpersonal/family issues and minor day-to-day activities rather than problem-based activities associated with work and/or school.40, 41, 63 Children experiencing GAD symptoms also worry more pervasively than children experiencing symptoms of other anxiety disorders and nonanxious controls.28, 64–66 They do however worry about the same events/activities, including personal health, family, and school, as nonanxious children but at a greater intensity.67–69
Reports since the release of DSM-IV are consistent with these findings upon which the DSM-IV Anxiety Work Group adult criteria reviews relied. Roemer et al.70 examined separately a clinical group with a primary GAD diagnosis (N=97 GAD; 48 controls) and a college group (N=137 GAD; 120 controls). Both GAD groups reported more worry domains (i.e., more generalized worry) than nonanxious controls and worried more about family/interpersonal and miscellaneous topics such as minor matters and routine daily activities. GAD patients also worried about more topics, particularly people/relationships, finances, religion/politics/environment, and “daily hassles” than those with social phobia.71 Older patients with GAD (N=36, mean age=68.4 years, SD=8.2) also report more pervasive worry than those experiencing sub-threshold-anxiety (defined as respondents who sought treatment for anxiety but who did not satisfy full DSM-IV criteria for any disorder, N=22) particularly about minor matters, finances, social/interpersonal matters, and their personal health. This sub-threshold group, however, did report more generalized worry than nonanxious controls (N=32).72 Diefenbach et al.73 reported slightly discrepant findings to this, suggesting that older GAD patients worry more than controls but do not worry about significantly different topics.
Others have indicated that worriers often couch their worries in terms of personal ineptness.74 Vasey and Borkovec75 conducted content analyses on all steps from “catastrophizing” interviews in which participants were asked to state all the negative consequences of areas of worry (e.g., If I received a negative evaluation at work, then …). Worriers generated proportionally more “failure/ineffectiveness” content than nonworriers. These results were consistent with a follow-up study by Davey and Levy,76 in which trait worry scores correlated positively with both the number of catastrophizing steps generated and independent judges' ratings of the content as “feelings of personal inadequacy.” Hazlett-Stevens and Craske77 replicated this in their study of content of catastrophizing across six different domain areas of threat among controls and analog GAD participants.
DSM-IV CRITERION B: DIFFICULT-TO-CONTROL WORRY
The perception of control over worry is negatively associated with anxiety, that is, the more control an individual perceives over their worry the fewer anxiety symptoms they report.90–92 Yet surprisingly few data are available regarding the importance of Criterion B to the GAD diagnosis. From clinical experience, the notion of “difficult-to-control” may be difficult for children to understand and it does not appear that children experiencing other GAD symptoms actually attempt to stop their worry. Consequently, reliance on children's self-reports alone may result in under-diagnosis notwithstanding that some children and adolescents will recognize that their worries are difficult-to-control. It may be that before children are able to attempt worry control, they require some higher meta-cognitive capacity that allows them to reflect on their worry and identify that it may be out of control. It is unclear whether children who have not reached formal operations have the capacity to do this, and if they do, it may reflect a particularly severe form of GAD. Consistent with this supposition, Tracy et al.28 in their comparison of DSM-III-R OAD and DSM-IV GAD criteria show that parental report of uncontrollability of worry correlated higher with the clinician's severity of the child's symptoms and level of distress/impairment (r=.62 vs. r=.87). They concluded that “children may have difficulty articulating the concept of uncontrollability, and therefore parent report of uncontrollability might be especially important', p 412.
A number of cognitive models address the role that perceived and actual differences in the ability to control worry play in GAD. For example, the meta-cognitive model espoused by Wells93, 94 holds that although individuals with a variety of anxiety disorders believe worry is a useful coping strategy (positive beliefs about worry), individuals only with GAD have negative beliefs about worry (i.e., “worry about worry”), such as that their worry is uncontrollable and/or dangerous.95 Ruscio and Borkovec96 used the Meta-Cognitions Questionnaire97 to compare beliefs about worry held by college students who met GAD criteria with a group of non-GAD high worriers (N=30 GAD; 30 non-GAD high worriers). Despite comparable worry severity, the two groups differed in their perception of their worry; the GAD high worriers were significantly more likely to regard their worry as harmful, dangerous, or out of control. In contrast, both high-worry groups reported positive beliefs about their worries. Ruscio and Borkovec also compared the non-GAD high worriers to a group of nonanxious controls used in the validation of the questionnaire. Slightly inconsistent with the meta-cognitive model, they found that the negative belief that worry is uncontrollable and dangerous was not unique to the GAD group: GAD worriers were more likely to consider their worry as uncontrollable and dangerous than non-GAD high worriers, who reported their worries to be more uncontrollable and dangerous than nonanxious controls. Finally, Ruscio and Borkovec examined uncontrollable worry experimentally and found that GAD and non-GAD high worriers differed in their control over worry following a worry induction, although group differences dissipated quickly. Initial research suggests that the perception of control over worry may be dimensional rather than providing a categorical distinction between GAD worriers and controls, but more evidence is needed.
Recent research shows that if the difficult-to-control criterion were omitted in DSM-V, it would have little impact on the identified cases (NSMHWB-2; EDSP).62, 81 For instance, in the NSMHWB-2, a representative Australian community sample, a more broadly defined GAD that includes both difficult and nondifficult to control worry would increase lifetime prevalence in treatment-seeking populations from 4.21% for DSM-IV GAD to 4.57%.
The majority of the variance that the difficult-to-control criterion contributes to the classification may be explained by the excessiveness criterion: Could a worry be excessive but still controllable? Clinical opinion would suggest not. In support of this conclusion, in the EDSP only ∼4% of respondents who satisfied all other DSM-IV criteria for GAD reported that their worry was excessive but was still controllable.62 There is no evidence on whether removing the difficult-to-control criterion would have the same effect in clinical samples as it does in the community.
If “difficult-to-control” is not redundant with “excessive,” does it help distinguish GAD from other anxiety and mood disorders and from healthy controls? Unfortunately, there are limited data on the discriminant validity of the difficult-to-control criterion but Hoyer et al.71 showed that GAD patients find their worry more difficult-to-control than patients with social phobia and nonanxious controls.
DSM-IV CRITERION C: THE ASSOCIATED SYMPTOMS OF GAD
Revisions to the associated symptom criterion have previously relied on the rationale that the items most frequently endorsed by patients with GAD should be retained and those items least frequently endorsed should be omitted from the classification.39, 88, 98 The removal of the autonomic hyperarousal symptoms from DSM-III-R to DSM-IV was also based on psychophysiological data comparing patients with GAD to nonanxious controls.99, 100 Subsequent research has shown that the associated symptom items retained in DSM-IV are among the most highly endorsed from the DSM-III-R list in children and adults,28, 34, 101–104 though it has been reported that “nausea, diarrhea, or other abdominal distress” are also highly endorsed by some adults.103, 104 Of the retained symptoms, parents tend to report more somatic symptoms than their children.105
The DSM-III-R motor tension, and vigilance and scanning symptom clusters also distinguish primary GAD from other primary anxiety disorders but they did not distinguish GAD from primary MDD (N=390 total; 73 principal GAD diagnoses). Nevertheless patients with GAD did endorse significantly greater autonomic hyperactivity than MDD patients.106 Although the latter symptom cluster may distinguish GAD from MDD, according to the rationales and evidence relied upon by earlier revisions, this would decrease the discriminant validity of the diagnosis with nonanxious respondents.
Although data post-DSM-IV predominantly supports the decision to retain the associated symptoms included in DSM-IV, Kubarych et al.104 queried whether this method alone provides a justifiable basis for omitting symptoms. They suggested that the least endorsed symptoms may reflect the most severe form of the disorder and will thus be lower in frequency (or at least distributed across the severity continuum). Kubarych et al. concluded that attempts to increase the discriminant validity of the associated symptoms criterion by reducing the number of symptoms39, 88 was not successful, given that in a factor analysis MDD, panic disorder, specific phobia and alcohol dependence all loaded on the GAD symptom factor. The associated symptoms of GAD are also the second largest source of discrepancy between GAD in DSM-IV and ICD-10. Approximately half of the respondents who endorse all DSM-IV criteria would not satisfy ICD-10 criteria because they did not endorse at least one of the four autonomic arousal symptoms.61
The DSM-IV associated symptoms “restless or feeling keyed up or on edge” and “muscle tension” are specific to GAD. The others are not. For example, fatigue, difficulty concentrating, and sleep disturbance occur in major depressive episodes; and irritability and sleep disturbance occur in post-traumatic stress disorder. How many associated symptoms should be required? In children, requiring either the child or parent to endorse at least one symptom from the six DSM-IV symptoms increases the sensitivity and specificity of the diagnosis.28 In adults the change in threshold to three symptoms from six symptoms in DSM-III-R was adopted with little empirical support for the discriminant validity and utility of the change. Brown et al.106 evaluated this threshold and found it to be quite sensitive, with 98.6% of the positive DSM-III-R GAD patients also endorsing the DSM-IV three or more threshold. However, the specificity of the threshold was low in relation to principal diagnoses of other anxiety disorders (.307) and MDD (.071). When the threshold was increased to four from six symptoms, the specificity and thus discriminant validity also increased (.478), whereas sensitivity remained relatively stable (.973).
In representative community samples, reducing the number of associated symptoms required makes little difference for the prevalence of GAD. For example Ruscio et al.80 showed that requiring two rather than three symptoms had little effect on prevalence. Reducing it to one symptom had negligible further effect (EDSP).62 Although effects were small they were larger in children/adolescents than adults providing some, albeit limited, support for the associated symptom criteria with a threshold of one symptom in these younger cohorts. In the first Australian NSMHWB, deleting criterion C altogether increased the 12-month prevalence by 4.2%. The individual symptoms are endorsed by the majority of people with GAD (restless: 88%; keyed-up: 89%; fatigued: 79%; difficulty concentrating: 82%; irritable: 82%; and muscle tension: 59%. Data are available on request). If however, deleting them has little effect on the prevalence of the disorder there seems little point in retaining the nonspecific associated symptom criteria (i.e., fatigue, difficulty concentrating, sleep disturbance, and irritability). The symptoms which are specific and endorsed by most respondents with DSM-IV-defined GAD (i.e., restlessness or feeling keyed up or on edge, muscle tension), if retained could increase or at least maintain the discriminant validity of the criteria from other mood and anxiety disorders.
The core symptom of GAD is cognitive, and the DSM-IV-associated symptoms are cognitive, affective and physical manifestations of hypervigilance and tension. There appears to be consensus, as reviewed above, that worry is a cognitive avoidant mechanism but could the manifest behaviors (i.e., avoidance behaviors) associated with these cognitions be identified? Could including these behaviors in DSM-V increase the reliability and the validity of the GAD diagnosis?
Given that worry appears to be used as an avoidant strategy particularly by adults and that this may be done explicitly, it is not surprising that these models—especially the cognitive avoidance, meta-cognitive, and intolerance of uncertainty models—propose that GAD patients have positive beliefs about their worries. However, positive beliefs about worry appear to be general markers of the anxiety disorders55, 107 and of severe worry in the absence of GAD96 rather than specific markers of GAD, and so they may not have sufficient utility to be added to the associated symptoms criteria.
GAD patients may engage in avoidant behaviors because of an intolerance of uncertainty. This could result from their beliefs that uncertain situations and the implications thereof are “stressful and upsetting, that being uncertain about the future is unfair, that unexpected events are negative and should be avoided, and that uncertainty interferes with one's ability to function.”47 Intolerance of uncertainty shows some symptom and diagnostic specificity. In nonclinical adolescent and adult samples it is positively related to worry108, 109 and shows a stronger relationship with worry than with other anxious and depressive symptoms, although there is some overlap with depressive symptoms110, 111 and there are reports of equally strong relationship with obsessive–compulsive symptoms.112 In their nonclinical adolescent sample, Laugesen et al.109 showed that compared to positive beliefs about worry and negative problem solving orientation, intolerance of uncertainty was the greatest predictor of the experience and severity of worry. In clinical samples, intolerance of uncertainty is more characteristic of GAD than other anxiety disorders,107 and in nonclinical respondents intolerance of uncertainty is related to worry more than depression.55 Patients with severe GAD also have a greater intolerance of uncertainty than those with milder forms of the disorder.113 Furthermore, intolerance of uncertainty can be modified and changes are associated with corresponding increases or decreases in worry.114 Increased tolerance of uncertainty also is associated with and typically precedes decreases in worry during treatment.115
In addition to avoiding uncertain situations, patients with GAD are known to engage in checking behaviors. The term “checking” is used here tentatively because of its association with OCD. Nonetheless these behaviors can be differentiated across the two disorders in terms of the focus of the checking. Patients with OCD tend to focus their checking on objects, whereas GAD patients tend to focus their checking on relational situations and achievement.116 The focus of these behaviors may be particularly important in differentially diagnosing OCD and GAD in children. GAD patients are also known to seek reassurance from others in response to their worries117 and use checking behaviors as an avoidant strategy.118 Reassurance was definitional for DSM-III-R OAD,20 and in our clinical experience excessive reassurance seeking is a particularly common characteristic of GAD in children. Moreover, GAD patients procrastinate; that is, they delay making decisions or behaving in certain ways a great deal more than would be expected and this can also be thought of in terms of the cognitive avoidance model of worry. It is difficult for GAD patients to make decisions because they could make the “wrong” decision and this is associated with negative emotions and hence should be avoided.
There are no data yet to inform where the threshold for this criterion should be set if specific behaviors are introduced in DSM-V as part of the GAD diagnosis or how it might best be operationalized. The option given below suggests that one or more avoidance behavior is reported but this is preliminary and the formal threshold will be informed by testing the proposed criteria.
DSM-V OPTION FOR THE ASSOCIATED SYMPTOMS OF GAD
The DSM-III-R symptoms retained in DSM-IV are the associated symptoms most frequently endorsed by GAD patients, but several are largely nonspecific to GAD. “Restless or feeling keyed up or on edge” and “muscle tension” are specific to the diagnosis and are also endorsed by most adult respondents with GAD and the former endorsed by most children and adolescents with GAD. If the nonspecific symptoms are omitted in DSM-V, it may increase the discriminant validity of the diagnosis particularly in relation to MDD, which has the largest symptom overlap with GAD. There is little evidence to support the current cutoff of three symptoms or to advocate an alternative threshold if all the DSM-IV associated symptoms were retained. Theoretical models of GAD suggest that the inclusion of criteria reflecting avoidant cognitive strategies in GAD and patients' associated behaviors with worry may benefit the DSM-V classification. The impact of their inclusion on diagnostic reliability, validity, and utility of adding such criteria has yet to be established.
Option for Criteria B and C of DSM-V GAD
B. The anxiety and worry are associated with one (or more) of the following symptoms:
C. The anxiety and worry leads to changes in behavior shown by one (or more) of the following:
marked avoidance of potentially negative events or activities
marked time and effort preparing for possible negative outcomes of events or activities
marked procrastination in behavior or decision-making due to worries
repeatedly seeking reassurance due to worries.
DSM-IV CRITERIA D AND F: HIERARCHICAL EXCLUSION CRITERIA
There has been little examination of the importance of the hierarchical exclusion criteria in GAD adults and no study of their influence on childhood GAD diagnoses. It is likely that these hierarchies particularly Criterion F are conceptual remnants of GAD's residual status in DSM-III. Given that other criteria have been introduced that establish the diagnostic independence of GAD, Criteria D and F may be of little importance to the DSM-V classification particularly Criterion F.
Many epidemiological studies that do not apply the hierarchical exclusion criteria have been able to identify differences between GAD and the other anxiety and mood disorders on external validating criteria.10 In one of the few direct examinations of the influence of Criterion F on casedness, Zimmerman and Chelminski121 compared patients with comorbid MDD and GAD; patients who experienced GAD only during the course of their depression (i.e., satisfied all GAD criteria except Criteria F); and patients with MDD but not GAD. The two GAD groups did not differ in terms of clinical or psychosocial correlates, or in their family history of anxiety, depressive, or substance-use disorders. Similarly, in their recent work Lawrence et al. show that the hierarchy imposed by this exclusion criterion with the mood disorders is obscuring the clinical features of GAD patients.122 Patients who reported GAD criteria except Criteria F and patients who experienced comorbid GAD/MDD were more severe, more neurotic and more impaired than patients who experienced MDD but not GAD. These findings suggest that the hierarchical exclusion criteria are excluding patients from the GAD diagnosis who, in terms of correlates could be considered disordered. It may be that, in practice, this has caused the overuse of the MDD or the otherwise not specified categories. These findings provide some support for reconsidering the utility of the hierarchies imposed by criteria D and F.