A range of etiological theories have been proposed for OCD (e.g., psychological, biological and neuropsychological). However, cognitive-behavioral models of OCD have generated a large body of empirical support and have led to the development of effective treatments (see Frost & Steketee, 2002). Other etiological theories for OCD have supported biological and structural brain abnormalities (see Pigott & Seay, 1996) and neuropsychological factors such as memory deficits (e.g., Tallis, Pratt, & Jamani, 1999). However, inconsistencies of findings and interference of confounding variables make interpretation difficult. For instance, while some OCD sufferers show abnormal brain structures, many do not (Cottraux & Gerard, 1998; Riffkin et al., 2005). Further, neuropsychological deficits (e.g., visuo-spatial memory impairment) may be a reflection of OCD symptoms rather than causal factors, such that impaired performance on specific memory tasks may reflect uncertainty and inability to make decisions rather than neurological deficits per-se (Otto, 1992). Moreover, such models have difficulty accounting for the effectiveness of behavioral and cognitive treatment in OCD.
Cognitive models suggest that dysfunctional beliefs and maladaptive appraisals underlie unhelpful strategies in the management of intrusive phenomena. Such strategies lead to extreme reactions to specific intrusive thoughts, images, or urges resulting in obsessive and compulsive symptoms (Clark & Purdon, 1993; de Silva & Rachman, 1998; Rachman, 1998; Salkovskis, 1985). Empirical research has indicated that the vast majority of the population experience intrusions at times, and that the difference between common intrusive thoughts and "obsessions" is in terms of the frequency, intensity, duration, discomfort and misinterpretations elicited by the thoughts, rather than in the content of the intrusions (Rachman & de Silva, 1978; Salkovskis & Harrison, 1984).
Recent cognitive-behavioral research by the Obsessive Compulsive Cognitions Working Group (OCCWG, 1997) has focused on six main belief domains that play an important role in the development of obsessions from intrusive thoughts: inflated personal responsibility, overimportance of thought, beliefs about the importance of controlling one's thoughts, overestimation of threat, intolerance for uncertainty and perfectionism. More recently, the OCCWG (Steketee et al., 2003; Taylor, Kyrios, Thordarson, Steketee, & Frost, 2002) reported not only a high degree of association between the identified belief domains and OC symptoms, but also high intercorrelations between scales measuring the six domains. Further, examination of the factor structure of a scale measuring these cognitive domains identified three larger factors (inflated sense of responsibility/overestimation of threat, perfectionism/intolerance for uncertainty and importance/control of thoughts), but, again, these were highly intercorrelated (OCCWG, 2005). This raises questions about possible higher order cognitive vulnerabilities that may account for such high intercorrelations.
Further, a substantial proportion of individuals with OCD do not show high levels of these dysfunctional beliefs (Taylor et al., 2006), suggesting that other beliefs may be important in this disorder. Finally, cognitive theories have been criticized for not sufficiently addressing the motivational base of the disorder (O'Kearney, 1998, 2001) although counter arguments have been raised (e.g., Salkovskis & Freeston, 2001).
Cognitive conceptualizations of OCD have implicated, explicitly or implicitly, the significance of self perceptions and assumptions about the world in the determination of responses to intrusions. Rachman (1997, 1998) has argued that "catastrophic misinterpretations" of the personal significance of intrusive thoughts are the main cause of the development and maintenance of obsessions. According to Rachman, intrusive thoughts which are perceived by the individual as endangering their view of self will trigger an escalation in dysfunctional behaviors, or cause a more intense use of thought-control strategies (e.g., thought-suppression).
According to Rachman, two cognitive biases increase the likelihood of catastrophic misinterpretations of intrusive experiences. The first bias involves the conviction that thinking about an unpleasant situation makes it more likely or probable to occur in reality. For instance, thinking about an accident involving a loved one will increase the probability of it happening in real life. The second, a moral bias, involves the conviction that having an immoral thought is morally equivalent to immoral actions. For example, the thought that having a sexual fantasy about someone other then one's own partner is morally equivalent to adultery. Thus, according to Rachman, intrusive thoughts become more distressing as they are appraised as revealing some hidden aspect of the self (e.g., I am immoral for having such intrusions) and as leading to predictable consequences in the world (i.e., a thought leads to a specific consequence in the world). These two biases constitute the concept of "thought-action fusion" (TAF) - a propensity to overestimate the significance of one's intrusive thoughts (Shafran, Thordarson, & Rachman, 1996; Rachman, 1998; see also Wells, 1997).
Rachman (1997, 1998; Rachman & Hodgson, 1980) suggested that the specific content of intrusions, such as themes of aggression, sex, and blasphemy, play an important role in this process by serving as the initial trigger for dysfunctional appraisals. Hence, Rachman emphasizes both the content of the intrusions and the presence of dysfunctional beliefs, including self-appraisals, in the process of intrusions becoming obsessions.
Similarly, Clark and Purdon (1993; Purdon & Clark, 1999) proposed that the appraisal of a thought as inconsistent with an individual's sense of self and/or beliefs and values (i.e., as ego-dystonic) together with higher-order beliefs regarding the importance of thought control (e.g., "I should be able to control my thoughts") are the main contributors to the exacerbation of obsessions. The ego-dystonic character of the specific thought perpetuates the saliency of the thought, making it the focus of attention. In turn, the meta-belief that it is possible to completely control one's thoughts promotes excessive thought control efforts (e.g., thought suppression) which are seldom completely successful and can cause a negative appraisal (including self appraisal) of the failure to suppress one's thoughts. This creates a negative feedback loop, which leads the individual to attribute even greater significance to controlling his/her thoughts (strengthening the meta-belief) and to more thought control efforts. A cycle is formed whereby an escalation in the frequency and saliency of the thought is caused along with increased distress and resistance to it. Recent evidence (e.g., Rowa & Purdon, 2003) supports the idea that the distress evoked by intrusive thoughts is related to the content of the intrusions and the individual's self-perceptions.
Salkovskis (1985, 1999) proposed that specific intrusions become more frequent, intense, and distressing as a result of a person's inflated sense of personal responsibility. Salkovskis defined an inflated sense of responsibility as a person's tendency to believe that they may be pivotally responsible for causing or failing to prevent harm to themselves or others. According to this view, an inflated sense of responsibility causes one to develop certain patterns of response to specific (rather than all) intrusive thoughts, impulses, or images. These patterns of response are attempts to neutralize (put matters "right" and make amends for) the unwanted intrusions, thereby reducing the distress caused by them. Examples of "neutralizing" include thought-control strategies such as thought suppression, deliberately thinking good thoughts, or compulsive acts such as hand-washing and constant rechecking for possible sources of danger (Freeston & Ladouceur, 1997). Thus, like Rachman (1997, 1998), Salkovskis' conceptualization of OCD implies that individuals with OCD hold particular perceptions of self and the world (i.e., harm is preventable in the world and one is able to prevent harm).
However, Salkovskis also argued that neutralizing behaviors in and of themselves lead to a debilitating cycle that reinforces the person's sense of responsibility and the subsequent negative appraisals of the thought. The temporary reduction of anxiety caused by neutralizing and its "success" in preventing the dreaded event is purported to reinforce the belief that one's actions are pivotal in preventing harm, thereby leading to an escalation in the frequency of the neutralizing. This in turn focuses even more attention on the intrusive thought, image or impulse, increasing its perceived frequency and the significance attached to its content or occurrence.
Salkovskis et al. (1999) also proposed that the development of an inflated sense of personal responsibility may be associated with "a high degree of conscientiousness, marked by dedication to work and an acute sense of social obligation" (Salkovskis et al., 1999; p: 1060). This implies that such individuals are likely to attribute an increased importance to specific domains of self (e.g., self as a moral being) and that this influences their response to specific intrusive thoughts.