Thought suppression: specificity in agoraphobia versus broad impairment in social phobia?

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Abstract

The paradoxical effects of intended thought suppression have been linked to psychological disorders, specifically anxiety disorders. So far, the evidence for thought suppression playing a major role in the disorder is mixed. One important issue is whether thought suppression is impaired only for thoughts related to the disorder, or if the ability for mental control is generally impaired in anxiety patients.

This study compared groups of agoraphobics and social phobics with a healthy control group. All subjects were asked to suppress two topics related to the respective central fear of the two disorders and one non-specific topic. We found a rather specific deficit in thought suppression for the agoraphobics; that is, when compared with the control group, we found the biggest differences for the agoraphobic fear. The social phobics seem to be characterized by a general impairment of mental control, affecting specific and non-specific stimuli. In addition, among several psychopathological variables, social anxiety proved to be the strongest predictor for problems with thought suppression. Taken together, there are several indicators that generally impaired thought suppression may be an important feature of social phobia.

Introduction

In 1987 Wegner and colleagues published a study describing the effects of intended thought suppression (Wegner, Schneider, Carter, & White, 1987). The group found that intended thought control produces paradoxical effects by enhancing the frequency of the thought to be suppressed after the suppression instruction is withdrawn. This unexpected result was named rebound effect.

Since then, many studies have investigated thought suppression, with variations in instructions for the expression period, in the method of thought sampling, and with different stimuli to suppress (ranging from personally irrelevant material to recollections of personally relevant events in the past). With regard to the rebound effect, these studies produced mixed results: some authors found the rebound effect for personally non-relevant material (Clark, Ball, & Pape, 1991, Rutledge, Hollenberg, & Hancock, 1993, Kelly & Kahn, 1994, Study 2; Rutledge, Hancock, & Rutledge, 1996, Wegner & Gold, 1995; Wegner, Schneider, Carter, & White, 1987, Wegner, Schneider, Carter, & White, 1987; Wegner, Schneider, Knutson, & McMahon, 1991, Wenzlaff, Wegner, & Klein, 1991), while others found an increase in thought frequency only for personally relevant material (Smári, Birgisdóttir, & Brynjólfsdóttir, 1995). Some authors found no rebound effect at all, but did demonstrate an increase in thought frequency during the suppression period: an immediate enhancement effect (Merckelbach, Muris, van den Hout, & de Jong, 1991, Muris, Merckelbach, & de Jong, 1993, Salkovskis & Campbell, 1994). Finally, some studies found neither of the two possible paradoxical effects of thought suppression (Kelly & Kahn, 1994, Study 1; Muris, Merckelbach, van den Hout, & de Jong, 1992, Muris, Merckelbach, Horselenberg, Sijsenaar, & Leeuw, 1997, Muris, de Jongh, Merckelbach, Postema, & Vet, 1998, Salkovskis & Campbell, 1994, Smári, Sigurjónsdóttir, & Sæmundsdóttir, 1994).

Regardless of the mixed evidence for rebound or enhancement effects following thought suppression, these effects have been used to explain the development and maintenance of psychological disorders characterized by unwanted thoughts. Most models concern obsessive–compulsive disorder and generalized anxiety. The assumed central mechanism relates to prolonged efforts to suppress unwanted thoughts—which produce paradoxical effects. As the person tries harder and harder to suppress, a circulus vitiosus is set. For simple phobia, Muris et al. (1998) reported that dental phobics showed higher levels of intrusive and negative thinking during dental treatment than non-phobics. They also demonstrated that dental phobics engaged a lot more in thought suppression during dental treatment than a control group. They conclude that their results are “. . . consistent with the notion that thought suppression plays a role in psychopathological conditions such as the anxiety disorders” (p. 285) as previously formulated by Wegner (1989). In a second study, conducted with spider phobics, the authors withdraw from this general view. Their study of thought suppression in spider phobics (Muris et al., 1997) found only minimal effects of thought suppression increasing the frequency of spider-related thoughts. They argue that this unexpected result may be because spider phobics cope with their fears predominantly in a behavioural way, so that effects in cognitive variables would be small. This is plausible, as a spider is a very concrete object of fear. But what would happen in phobic patients with more vague objects of fear or with a wide variety of stimuli which evoke fear, as is the case with social phobia and agoraphobia?

So far, no studies using these populations have been published. The present study aimed to fill the gap. Two clinical groups with social phobia and agoraphobia respectively were compared with a healthy control group. An important question was whether problems with thought suppression exist only for a disorder-related topic, or if there is a generally impaired mental control. This distinction is relevant in determining the role of the impaired mental control within the model of development and maintenance of the disorder.

Section snippets

Interviews

A structured interview was conducted with all of the patients. We used the ADIS-R (Anxiety Disorders Interview Schedule-Revised; DiNardo & Barlow, 1988) in its German version (DIPS, Diagnostisches Interview bei Psychischen Störungen; Margraf, Schneider, & Ehlers, 1991). The DIPS uses DSM-III-R criteria and explores anxiety disorders, eating disorders, affective disorders and substance misuse. It also contains a screening for psychotic disorders. For the control group we used the short version

State anxiety and ratings of the experimental material

The state anxiety measured by the State trait anxiety inventory revealed no pre-experimental differences between the groups (agoraphobics: M=41.1, SD=3.94; social phobics: M=40.7, SD=4.79; controls: M=43.7, SD=9.34; F(2, 87)=1.74, p=0.18). Furthermore, we found a significant decrease in anxiety during the experimental task (mean between the three groups before the experiment: M=41.9, SD=6.53; after: M=40.5, SD=5.11; t(89)=2.4, p<0.018).

In the characteristics associated with the material to

Discussion

In this study we aimed to establish whether phobic patients show specific, disorder-related impairments in controlling their thoughts, or if the patients have general deficits in thought control. Unexpectedly, the results revealed different patterns for the two clinical groups. Patients with agoraphobia showed a more specific effect, whereas the social phobics seem to be generally impaired in controlling unwanted negative thoughts.

One might assume that the group differences in thought

References (35)

  • A.T Beck et al.

    An inventory for measuring clinical anxiety: psychometric properties

    Journal of Consulting and Clinical Psychology

    (1988)
  • A.T Beck et al.

    Beck Depression Inventory Manual

    (1987)
  • J Cohen

    Statistical power analysis for the behavioral sciences

    (1988)
  • L.R Derogatis et al.

    The SCL-90-R: an outpatient psychiatric rating scale—preliminary report

    Psychopharmacology Bulletin

    (1973)
  • P.A DiNardo et al.

    Anxiety Disorders Interview Schedule—Revised (ADIS-R)

    (1988)
  • Fehm, L., Dilcher, K., & Margraf, J. (in press). Die Unterdrückung unerwünschter Gedanken: Vergleich zweier Varianten...
  • G.H Franke

    Die Symptom-Checkliste von Derogatis [German version]

    (1995)
  • Cited by (0)

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