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Article Excerpt
The cognitive-behavioural theory of obsessive-compulsive disorder (OCD) proposes that cognitive content and processes are central in the aetiology and maintenance of the disorder. Researchers responsible for pioneering the cognitive theory of OCD contend that obsessions represent the extreme end on a continuum of normal, unwanted, intrusive cognitions (Rachman, 1981; Salkovskis, 1985, 1989). They argue that these negative and unwanted intrusive thoughts play a crucial role in the development of the clinical obsessions (Clark & Purdon, 1993; Rachman, 1981; Rachman & Hodgson, 1980; Salkovskis, 1985, 1989). A number of empirical studies have supported this idea, demonstrating that almost 90% of non-clinic individuals report experiencing frequent intrusive thoughts, images, or impulses (Parkinson & Rachman, 1981; Rachman & de Silva, 1978; Salkovskis & Harrison, 1984), and that these intrusive thoughts are often indistinguishable in 'content' from those experienced by obsessive-compulsive individuals. Normal intrusive thoughts appear to differ from obsessional thoughts, however, in that they occur less frequently, they are interpreted with less emotionally intensity, they are more controllable, and they are less likely to be associated with overt or covert ritualising (Clark & Purdon, 1993). Researchers in the field argue that specific cognitive biases, associated with the interpretation of these normal intrusive thoughts, might account for the development and maintenance of obsessions, and consequently clinical OCD.
Cognitive appraisals of risk (including perceived severity and probability of harm) and responsibility for harm are central processes in the cognitive theory of OCD (Rachman, 1976, 1993; Salkovskis, 1985, 1989). Risk appraisals of inflated harm probability refer to beliefs related to the likelihood of aversive events occurring, while appraisals of inflated harm severity refer to beliefs about the personal cost that may result from the occurrence of aversive events. Salkovskis (1985, 1989) considerably advanced the cognitive theory of OCD by proposing that the interpretation of negative intrusive thoughts, as indicating personal responsibility for harm to self or others, leads to increased discomfort and anxiety, increased salience of the thoughts, and neutralizing behaviours, including overt and covert compulsions, avoidance behaviours, and thought suppression. In this way, an intrusive thought related to harm of others, for example, 'my daughter might be abducted during the night', would probably be interpreted by the obsessive-compulsive in the following way: 'if I don't check on my daughter all through the night, then she might be abducted and it would be my fault because I am responsible for protecting her'. A number of studies with adult samples, using idiographic, psychometric, and experimental designs, have tested the central components of the cognitive theory and have found moderate to strong support for cognitive biases of increased responsibility, probability, and severity of harm associated with obsessive-compulsive symptoms (i.e. Carr, 1974; Clark, & Purdon, 1993; Foa & Kozak, 1986; Freeston & Ladouceur, 1993; Freeston, Ladouceur, Gagnon, & Thibodeau, 1991; Freeston, Rheaume, & Ladouceur, 1996; Frost & Steketee, 1991; Lopatka & Rachman, 1995; Rheaume, Ladouceur, Freeston, & Letarte, 1994; Rheaume, Ladouceur, Freeston, & Letarte, 1995; Shafran, 1997; Steketee & Frost, 1994; Steketee, Frost, & Cohen, 1996).
Thought suppression is an example of one of the counterproductive escape/avoidance mechanisms associated with OCD. Thought suppression, largely developed and investigated by Wegner and colleagues (i.e. Wegner, Schneider, Carter, & White, 1987; Wegner, 1994; Wegner & Zanakos, 1994), refers to the voluntary effort to suppress or inhibit an idea, thought, or image, in an attempt to neutralize any anxiety or discomfort associated with the idea, thought, or image. Paradoxically, intentional thought suppression has been consistently found to result in a later rebound or resurgence of the unwanted thought following suppression attempts across both OCD and non-clinic samples (Clark, Ball, & Pape, 1991; Clark & de Silva, 1985; Rachman, 1993; Wegner, 1994; Wegner et al., 1987; Wegner, Schneider, Knutson, & McMahon, 1991). The finding that intentional control over unwanted thoughts is problematic for individuals is most evident in OCD, where sufferers are besieged by obsessions that seem near impossible to repress (Purdon & Clark, 2002). The lack of cognitive control over ones' thoughts/obsessions is a significant complaint associated with OCD. These cognitive efforts to control ones thoughts (i.e. through thought suppression), are argued to also be associated with the maintenance of obsessions and the disorder (see Purdon, 1999 for a review).
Other cognitive processes thought to be important in the maintenance of OCD are self-doubt (i.e. O'Kearney, 1998) and thought-action fusion (TAF; Rachman, 1993). Self-doubt is argued to be a distinctive feature of OCD and accounts for the indecisiveness characteristic of sufferers of OCD. TAF as described by Rachman (1993) is a cognitive process associated with OCD, where thoughts and actions concerning harm are experienced as equivalent. TAF involves a likelihood bias, whereby thinking of an aversive event (e.g. acting violently towards a loved one) is perceived as increasing the likelihood of that event occurring. In addition, TAF also involves a morality bias, whereby the obsessive-compulsive interprets thoughts concerning immoral behaviour (e.g. violence towards a loved one) as equally as bad as actually engaging in immoral behaviour (Shafran, Thordarson, & Rachman, 1996). Research has demonstrated that TAF is significantly correlated with obsessive-compulsive symptoms (Rachman, Thordarson, Shafran, & Woody, 1995); appears to be higher across obsessional samples in comparison to non-clinic samples (Shafran et al., 1996), and is associated with increased frequency of intrusive thoughts, higher discomfort, and more resistance of thoughts (Rassin, Merckelbach, Muris, & Spaan, 1999). In a recent investigative study of TAF, thought suppression and obsessive-compulsive symptoms, Rassin and colleagues (Rasin, Muris, Schmidt, & Merckelbach, 2000) found that TAF triggers thought suppression, which, in turn, promotes obsessive-compulsive symptoms.
While there is sufficient research support implicating these cognitive processes as maintaining features of adult OCD, only two preliminary studies to date have investigated the role of cognitive processes in the maintenance of childhood OCD. Barrett and Healy (2003) examined cognitive appraisals of threat in a sample of children with OCD (aged 7 to 13 years), and compared these with a sample of anxious and non-clinic children. Using an idiographic approach, as proposed by the Obsessive-Compulsive Cognition's Working Group (1997), this study assessed cognitive interpretations of perceived responsibility for harm, probability of harm, severity of harm, thought-action fusion, self-doubt, and cognitive control. It was hypothesized that, consistent with the cognitive theory of OCD in adults, children in the OCD group would display higher estimations of these cognitive processes in comparison to anxious and non-clinic children. Results revealed that OCD children reported significantly higher ratings of responsibility, severity, TAF, and less cognitive control in comparison to non-clinic children; however, there were few significant differences between anxious children and children with OCD. In fact, children with OCD could only be clearly differentiated from anxious children on ratings of cognitive control. These preliminary findings fail to find strong support for an OCD-specific cognitive theory in childhood. It was concluded from this study that these cognitive processes in OCD clients might become more prominent during adolescence, when cognitive development advances allowing children to be 'meta-cognitive', and when OCD might worsen in severity. An investigation of age-related differences may shed light on the issue of when cognitive processing associated with OCD might become apparent in younger samples.
In only the second study examining cognitive processing of threat in childhood OCD, Barrett and Healy-Farrell (2003) investigated the role of perceived responsibility in obsessive-compulsive symptomatology. Replicating the experimental paradigms of Lopatka and Rachman (1995) and Shafran (1997), perceived responsibility of threat was experimentally manipulated in a sample of children and adolescents with OCD, during a behavioural avoidance task (BAT). The effects of high responsibility on levels of perceived probability of harm, severity of harm, distress, ritualizing, and avoidance was examined. This study manipulated levels of perceived responsibility by varying the presence of others during a BAT and assigning responsibility using signed contracts between the child and the experimenter. Results indicated that the experimental manipulation was successful in inflating perceived responsibility for children and adolescents with OCD; however, an increased perception of responsibility for harm did not lead to increased perceptions of probability for harm, severity for harm, or levels of distress, as hypothesized and demonstrated in adult samples.
In this same study, Barrett and Healy-Farrell (2003) investigated whether cognitive-behavioural treatment (CBT) would decrease ratings across these cognitive processes, related distress, avoidance, and ritualizing during the high responsibility BAT at post-treatment. In terms of treatment outcome, there were significant reductions in diagnostic status, symptom severity, and cognitive processing of threat for children who completed the CBT family intervention, in comparison to children on a waitlist. Taken together, these two studies (Barrett & Healy, 2003; Barrett & Healy-Farrell, 2003) do suggest that children with OCD report somewhat inflated levels of these cognitive biases when compared with non-clinic children, and that CBT is effective in reducing these perceptions of threat. However, the first experimental study (Barrett & Healy-Farrell, 2003) investigating the cognitive processes in children and adolescents with OCD failed to find support for the critical role of responsibility, as proposed by Salkovskis (1985, 1989). As such, the current cognitive theory of OCD in adulthood may not adequately explain and account for the...
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