ویژگی های نگرانی در اختلال اضطراب فراگیر

Background & objectives Groups of clients and community volunteers with Generalized Anxiety Disorder (GAD) and clients with Panic Disorder were compared to a group with elevated worry but without GAD on a range of measures, to identify individual differences beyond a high propensity to worry. Method Participants completed standardised questionnaires and a behavioural worry task that assesses frequency and severity of negative thought intrusions. Results Relative to high worriers, clients with GAD had higher scores on trait anxiety, depression, more negative beliefs about worry, a greater range of worry topics, and more frequent and severe negative thought intrusions. Relative to community volunteers with GAD, clients in treatment reported poorer attentional control. Compared to clients with Panic Disorder, clients with GAD had higher trait anxiety, propensity to worry, negative beliefs and a wider range of worry content. Conclusions Results confirmed expectations of group differences based on GAD diagnostic criteria, but also revealed other differences in mood, characteristics of worry, and perceived attentional control that may play a role in the decision to seek treatment.

Worry is characterised by the repeated experience of thoughts about potential negative events, and reported proneness to worry varies continuously across the normal population (Ruscio, Borkovec, & Ruscio, 2001). Chronic, excessive and uncontrollable worry about multiple topics is the main defining feature of Generalized Anxiety Disorder (GAD; Diagnostic and Statistical Manual of Mental Disorders 4th Edition: DSM IV; American Psychological Association, 1994), often causing severe incapacity. In addition to excessive and uncontrollable worry, a diagnosis of GAD requires endorsement of at least three other associated symptoms (e.g., concentration problems, sleep difficulties, fatigue). However, given that excessive, uncontrollable worry is the central requirement for a diagnosis of GAD, it was the focus of the current study. Ruscio et al. (2001) reported that worry propensity lies on a normal continuum. Individuals with GAD are characterised by the presence of severe and uncontrollable worry. Some excessive worriers without GAD also report other associated symptoms although (necessarily) not in sufficient number to meet diagnostic criteria (Ruscio, 2002). Whether or not an individual experiencing high levels of worry also meets diagnostic criteria for GAD thus depends on multiple criteria that include the presence of somatic as well as cognitive symptoms. When multiple criteria must all be met to achieve a categorical distinction, it is not clear which among them are essential, or even useful, in distinguishing between diagnosed and non-diagnosed groups. The main aim of the present study was to test hypotheses derived from the worry-related criteria currently used to diagnose GAD, by assessing the extent to which they actually distinguish individuals with this diagnosis from a non-clinical group with similarly high levels of worry, or another anxiety disorder in which worry is not thought to be central, such as Panic Disorder. Failures to find predicted differences would have potentially important implications for the clinical or theoretical usefulness of the assumed central criteria. Furthermore, other differences emerging could inform attempts to formulate a comprehensive model of GAD and the development of more effective treatments. Summarized below are the main issues and questions to be addressed in the present study. (1) Range of worry topics. Although frequent worry about multiple topics is the central requirement for diagnosing GAD, it does not necessarily follow that the number of topics worried about actually distinguishes high worriers meeting diagnostic criteria for GAD from high worriers who do not meet all the required criteria; nor that frequency of worry distinguishes those with GAD from those with other anxiety disorders not defined in terms of the worry about many topics. We therefore explicitly tested the previously unexamined hypothesis that the range of worry topics would be greater in a group meeting diagnostic criteria for GAD than a matched high worry group not meeting these criteria or clients with Panic Disorder. (2) Perceived and actual control. Similarly, the fact that reported lack of perceived control over worry is required for diagnosing GAD does not necessarily mean that non-GAD high worriers actually have any greater control over worry than do those with GAD. Consequently, a further hypothesis tested in the current study was that those with GAD would be less able to prevent worrisome thoughts intruding when attempting to focus their attention elsewhere, and possibly also have a more general inability to control attention, based on a self-report questionnaire designed to assess ability to control attention across a range of everyday activities. (3) Beliefs about worry. Inappropriate beliefs about either the positive benefits or the negative consequences of excessive worry are not part of the diagnostic criteria for GAD, although some previous researchers (e.g., Ruscio & Borkovec, 2004; Wells & Carter, 2001) have found evidence suggesting that such beliefs may be both characteristic of the disorder and possibly play a part in maintaining it. Given these previous suggestions, we included a further examination of this issue using an established questionnaire measure (Meta Cognitions Questionnaire; MCQ; Wells & Carter, 2001) to test the extent to which beliefs about worry distinguish those meeting GAD diagnosis on clinical interview from equally high worriers not so diagnosed. (4) Other emotional differences. High levels of anxiety and depression often accompany excessive worry, although again the question of whether or not such mood disturbances accompany all elevated worry states, perhaps as a consequence of worry itself, or are more likely to occur in those meeting current criteria for GAD as assessed by clinical interview has not previously been examined. It is possible that it is only the emotional symptoms that are presently required for diagnosis of GAD which distinguish those meeting diagnostic criteria for GAD from others with equally intrusive and uncontrollable worries about similarly diverse topics. We assessed this possibility by comparing GAD and matched high worriers using standard questionnaire measures of trait anxiety (State-Trait Anxiety Inventory Trait version; STAI-T; Spielberger, Gorsuch, Lushene, Vagg, & Jacobs, 1983) and depression (Beck Depression Inventory; BDI; Beck & Steer, 1987). (5) Finally, not all those meeting criteria for GAD enter or even seek treatment and it is unclear how those not seeking help differ from similarly diagnosed groups in treatment, or for that matter from high worriers not so diagnosed. Little is known about the factors influencing individuals with similar symptoms to enter treatment or otherwise, but one obvious possibility is that those seeking treatment are experiencing greater severity in the worry-related or emotional symptoms discussed above. Another previously suggested hypothesis to be tested here is that the perceived failure of control over intrusive negative thoughts in worry is the critical factor leading high worriers to seek help (Mathews, 1990). In earlier work, Ruscio and Borkovec (2004) addressed some (but not all) of the issues discussed above, by individually matching pairs on overall worry severity (based on their Penn State Worry Questionnaire scores; PSWQ; Meyer, Miller, Metzger, & Borkovec, 1990), with one of each pair meeting GAD criteria (as assessed using the Generalized Anxiety Disorder-Questionnaire; GAD-Q-IV; Newman et al., 2002), while the other did not. Rather than relying on reported inability to control worry, Ruscio and Borkovec (2004) used a behavioural test in which participants attended to their breathing before and after instructed worry (cf. Borkovec, Robinson, Pruzinsky, & DePree, 1983), and when signalled on four occasions participants reported if they had been distracted by a negative, positive or neutral thought at the time of the signal. Those with a GAD diagnosis (based on questionnaire) were more likely to report a negative thought than were others not so diagnosed, but only on the first occasion immediately following instructed worry. Although consistent with impaired control in GAD the effect was surprisingly short-lived, so that reported lack of control may be more perceived than real and could partly reflect stronger negative beliefs about worry in the GAD group. Part of the present study (see Section 2 above) was similarly directed to the question of whether the characteristics of worry in clients diagnosed with GAD differ from those in a group of volunteers matched on overall reported worry severity. However, to further examine whether these groups differed in perceived or real ability to control thoughts (or both) we included a questionnaire measure of perceived control (Attentional Control Scale: Derryberry & Reed, 2002), and increased the frequency of thought samples in the behavioural worry measure to enhance sensitivity to actual control differences. Thought intrusions were also categorised in terms of valence by an assessor who was not informed about group membership to determine if negative intrusions were objectively more common in the diagnosed groups. Negative intrusions were also categorised by an assessor in terms of severity to assess whether people with GAD reported particularly negative thoughts. In addition, we distinguished between those in treatment for GAD and a community sample meeting GAD criteria (using the structured clinical interview for DSM-IV in addition to the GAD-Q-IV used by Ruscio & Borkovec, 2004 with their student sample) who were not seeking treatment. We also contrasted those in treatment for GAD with a group being treated for Panic Disorder, to determine whether any differences found applied generally to all those seeking treatment, rather than being specific to GAD. Clients with Panic Disorder are concerned about the potential occurrence of future panic attacks, so they may worry frequently about this specific issue. They are, however, less likely to worry about a wide range of worry topics, or be as concerned about the process of worrying itself, when compared to clients with GAD. Hence, inclusion of this latter group also allowed us to test the assumption that GAD (compared to panic disorder) is associated with a greater range of worries, and greater concern about worrying, but not necessarily with a higher frequency of worrying. Finally, to check whether groups also differed in mood state we also obtained measures of anxiety and depression at the time of testing.

In summary, the current study found evidence to support the specificity and utility of the GAD diagnostic criteria for differentiating clients with GAD from high worriers and clients diagnosed with Panic Disorder, as well other factors that differentiate treatment-seeking GAD clients from a community sample of individuals meeting GAD criteria. A number of differences were found to contribute to the differential diagnosis of GAD or Panic Disorder, including some that were expected given that diagnostic criteria for GAD focus on excessive worry about a wide range of topics. However, the number of negative intrusions in the worry task, as assessed independently, did not significantly differ between these clinical groups. Although future research is required to investigate generalization of the worry task to everyday situations, such findings suggested that, compared to Panic Disorder, clients with GAD have greater concern about their inability to control worry and its perceived negative effects (e.g., worry about worry; Wells, 1995), rather than there being differences in actual frequency or negativity of worry-related intrusions. Of particular interest were the distinctions found between high worriers and those with a diagnosis of GAD that support the assumption that those with GAD do experience a real excess of uncontrolled intrusive thoughts having more negative content, beyond that experienced by a high worry group reporting the same elevated propensity to worry. These findings suggest that the transition from high worry to diagnosable GAD is associated with an objective (assessor-rated) elevation in the distressing and intrusive properties of intrusive thoughts. In sum, the main factors assessed here that differentiated those with GAD (clinical or community) from high worriers without GAD were elevated trait anxiety and reduced ability to prevent particularly distressing thoughts from intruding into awareness (in the behavioural worry test). Given this, clinicians could consider including the behavioural worry task in clinical assessment of GAD. This would provide important information about actual lack of controllability of worry, over and above perceived uncontrollability provided by self-report. Furthermore, the worry task could also be included at the end of treatment to determine whether clients have indeed gained better behavioural control over worry, as would be needed to no longer meet criteria for GAD. The other noteworthy set of findings concerned the division of those with GAD according to their clinical status, that is, whether they were patients in or awaiting treatment, or were members of the community who were not seeking treatment. When only the clinical GAD group was compared with high worry participants, some additional differences in beliefs about worry emerged, although these were confined to its negative attributes, perhaps reflecting the perception of inability to control negative thoughts. Importantly, while this group of clients in treatment for GAD differed from high worriers without GAD in a number of other respects (such as low mood, and range of worries), individuals with GAD who were not currently seeking treatment did not significantly differ from high worriers in the same ways. This contrast suggests that differences found between clinical and non-clinical control groups (in this case clinical GAD vs. high worriers) that could be attributed to diagnostic status alone, may in fact be associated with treatment seeking status rather than diagnosis per se. Similarly, although diagnosis of GAD (clinical or community groups vs. high worriers) was not associated with differences in perceived inability to control attention (as assessed by ACQ), this factor did appear to contribute to the distinction between GAD clients currently in treatment and individuals with GAD who are not currently seeking treatment. Interestingly, therefore, rather than a further increase in the factors associated with a GAD diagnosis itself (such as a greater number of highly negative intrusions), it may be the perception of inability to control worry, together with the belief that it is important to control such thinking, that leads those with GAD to seek treatment. This implies that there may be important characteristics of those who find worry intolerable and thus seek treatment that are not captured by the diagnostic criteria alone. The differences between community and clinical GAD populations (and their respective differences from high worriers) could be taken into account when considering the best way to intervene clinically with individuals with GAD who seek treatment. For example, the factors leading to seeking help may be directly addressed by techniques that enable the client to realise they do have some control over worry, such as the use of negative thoughts as a cue to postpone worry and substitute more positive thoughts or activities. Treatment decisions of this sort can be guided by assessing both beliefs about control and actual control of intrusions in a behavioural worry test. Finally, we suggest that a complete account of causal factors in pathological worry needs to take the individual differences identified here into account, including the possible roles of perceived control. In a recent cognitive model of pathological worry (Hirsch & Mathews, 2012) we reviewed evidence supporting the interactive roles of habitual processing biases favouring threat content (e.g., Hayes, Hirsch & Mathews, 2010; Hirsch, Hayes & Mathews, 2009; Hirsch et al., 2011; Krebs, Hirsch & Mathews, 2010), and top-down attentional control (e.g., Bishop, 2009; Hayes, Hirsch & Mathews, 2008; Leigh & Hirsch, 2011) which can be used to oppose negative thought intrusions, or be captured by threatening content and lead to protracted worry. Such an interactive process is consistent with many of the present findings, but as discussed earlier, some findings suggest that a further distinction should be made between perceived and actual control. While actual control over negative thoughts distinguishes between those meeting GAD diagnostic criteria and those who do not, the perception of control seems more critical in obtaining treatment.