Abstract
Obsessive-compulsive disorder(OCD) is characterized by intrusive frightening thoughts, images or impulses (obsessions; e.g., “did I stab my partner while doing the dishes?”) to which patients respond with repetitive behavior (compulsions; e.g., checking the knives and scissors in the house or calling their partner to ensure he or she is alive)
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to suppress these unwanted thoughts and prevent misfortunes from happening (American Psychiatric Association, 2013). Repeated checking is one of the most common compulsion in OCD (Ruscio, Stein, Chiu, & Kessler, 2010). Many theories on the development and maintenance of OCD emphasize the role of obsessions and view compulsions as “output” resulting from frightening thoughts. However, checking compulsions may also be important for understanding how OCD develops and persists, since recent research showed that repeated checking paradoxically enhances memory distrust and checking may also be present in the absence of extreme obsessions. Therefore, this dissertation focused on the role of checking behavior in the development and maintenance of OCD symptoms, and how checking behavior and cognitive symptoms in OCD may mutually reinforce one another. In the first three studies we examined whether mild uncertainty, thematically unrelated to extreme obsessions, stimulates general checking behavior in OCD. A new eye-tracking paradigm was developed in which participants performed a visual search task and indicated in 50 search displays whether a target was “present” or “absent”. Target-present trials were unambiguous, whereas target-absent trials induced mild uncertainty, because participants had to rely on not overlooking the target. Results showed that in both target-present (certain situations) and target-absent trials (uncertain situations) patients with OCD engaged in more checking behavior (they checked longer and more precisely) than healthy and anxiety controls, but the difference between the groups was larger in target-absent trials than in target-present trials. Anxiety controls did not differ from healthy controls in checking behavior throughout the task. Therefore, mild uncertainty appears to specifically promote checking behavior in patients with OCD. In the last two studies we investigated whether checking behavior directly contributes to the exacerbation of OCD symptoms. First we showed that repeated checking seems to cause memory distrust every time this counterproductive strategy is used, which may fade once the checking episode has ended. Secondly, it was demonstrated that engaging in OC-like checking behavior for one week already increased obsession-related cognitions about threat severity when checking behavior would not be executed. Hence, checking behavior seems to have direct negative effects on cognitive symptoms in OCD. By demonstrating these reciprocal relationships between checking behavior and cognitive symptoms in OCD (i.e. mild uncertainty leads to checking and checking leads to memory distrust and obsessive cognitions) it became clear that checking behavior is more than just “output” of obsessive concerns and may play a role in the development of new OCD problems. Given the detrimental effects of this coping strategy, it may be involved in the transition between subclinical and clinical OCD, and general checking behavior may therefore be an important target for behavior treatment and relapse prevention in OCD.
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