Anxiety disorders: why they persist and how to treat themDavid M. ClarkDepartment of Psychiatry, Warneford Hospital, University of Oxford, Oxford OX3 7JX, UKAbstractAnxiety disorders are characterised by distorted beliefs about the dangerousness of certain situationsand/or internal stimuli. Why do such beliefs persist? Six processes (safety-seeking behaviours, attentionaldeployment, spontaneous imagery, emotional reasoning, memory processes and the nature of the threatrepresentation) that could maintain anxiety-related negative beliefs are outlined and their empiricalstatus is reviewed. Ways in which knowledge about maintenance processes has been used to developfocussed cognitive therapy programmes are described and evaluations of the eectiveness of suchprogrammes are summarized. Finally, ways of identifying the eective ingredients in cognitive therapyprogrammes are discussed. # 1999 Elsevier Science Ltd. All rights reserved.1. IntroductionCognitive theorists propose that anxiety disorders result from distorted beliefs about thedangerousness of certain situations, sensations and/or mental events. Consistent with thisproposal, numerous studies have shown that patients with anxiety disorders over-estimate thedangerousness of various stimuli. Several studies have also shown that such over-estimates aredisorder speci®c, with each anxiety disorder being associated with a particular type of negativebelief (e.g. Harvey, Richards, Dziadosz, & Swindell, 1993; Clark et al., 1997; Amir, Foa, &Coles, 1998; Breitholz, Westling, & OÈst, 1998; Salkovskis et al., in press; Foa, Ehlers, Clark,Tolin, & Orsillo, 1999; Stopa & Clark, in press). The present paper addresses a problem thatarises from these ®ndings. If anxious patients' beliefs are mistaken, why do the beliefs persist?Put another way, if the world is not as dangerous as patients assume, why do they not noticethis and correct their thinking? Answers to this question are likely to be particularly helpful inunderstanding the maintenance of anxiety disorders and developing ecient treatments.Behaviour Research and Therapy 37 (1999) S5±S270005-7967/99/$ - see front matter # 1999 Elsevier Science Ltd. All rights reserved.PII: S 0 00 5 - 7 9 6 7 ( 9 9) 0 0 0 4 8 - 0E-mail address: [email protected] (D.M. Clark)However, before discussing possible answers, it is perhaps worth mentioning some observationsthat highlight why the question is interesting.First, if one looks at the natural history of anxiety disorders it is clear that there are manypeople in the community who develop an anxiety disorder and then recover without anytreatment. For these people, their negative thinking seems to be self-correcting. Somethingappears to prevent such self-correction from occurring in patients who present for treatment.Second, for many patients with chronic anxiety disorders, the persistence of their fears seemsstrangely irrational. Consider, for example, chronic panic disorder patients, who think duringtheir attacks that they are having a heart attack. Before they come for treatment, they mayhave had several thousand panic attacks, in each one of which they think they are dying, butthey are not dead. Despite what might appear to an outsider to be stunning discon®rmation oftheir fears, their thinking has not changed. In particular, they do not seem to have spotted thattheir repeated failure to die does not ®t with the idea that the sensations they experience in apanic attack are a sign of a heart attack. After all, cardiologists do not report seeing patientswho have had thousands of non-fatal heart attacks.A similar problem arises in social phobia. Patients with social phobia are afraid of negativeevaluation from other people. As children, they have often been bullied and teased at school.However, as adults they rarely receive explicit negative evaluation from other people, despiteoften going into dicult social situations. Why, therefore, do they not notice that they comeacross better than they think?Below I describe Oxford research which has attempted to identify factors that preventpatients from changing their negative thinking normally. The research is very much acollaborative eort, involving many colleagues1. Six dierent maintaining processes: safety-seeking behaviour, attentional deployment, spontaneous imagery, emotional reasoning, certaintypes of memory processes and the nature of threat representations are discussed. Anillustration of the way in which each can maintain anxiety disorders is provided, along with asummary of experimental evidence for the process. The treatment implications of themaintenance processes are then described and illustrated, again with a summary of theirempirical status.2. Jack RachmanIt is ®tting that work focussing on why negative beliefs fail to self-correct should be outlinedin a special issue honouring the outstanding achievements of Jack Rachman. In his classiccritique of the conditioning theory of phobia, Rachman (1976) drew the ®eld's attention tomany of the puzzles about the persistence of anxiety. In subsequent articles (for example,Rachman & de Silva, 1978; Rachman, 1980, 1984, 1997; Rachman, Craske, Tallman, &1Most of the Oxford studies reported here were co-directed with Anke Ehlers or Paul M. Salkovskis. AnnHackmann, Freda McManus, Melanie Fennell, Adrian Wells, Gillian Butler, Candida Richards, and John Ludgatewere invaluable collaborators and made major contributions to the clinical studies. Warren Mansell, AllisonHarvey, Yi Ping Chen, Emma Dunmore, Sarah Halligan and Tanja Michael were similarly instrumental in the ex-perimental studies.D.M. Clark / Behaviour Research and Therapy 37 (1999) S5±S27S6Solyom, 1986; Radomsky, Rachman, Teachman, & Freeman, 1998) he provided perceptiveanswers to some of these puzzles. As a mentor, he encouraged my colleagues and I to closelyobserve patients and spot phenomena that did not ®t with current theories and to worry aboutthese phenomena. As an inspired journal editor, he has consistently spotted and supportedunusual contributions from behavioural scientists that ultimately became in¯uential. As aclinical supervisor, he taught me the value of `goonery' in therapy, though I cannot claim tohave achieved his exceptional mastery of the art. Finally, he was a pioneer, and expert teacher,of the type of clinical experiment that has become a central feature of the Oxford Group'swork. For all of these gifts, for his impeccable taste in wine and