اثر سرکوب و ارزیابی بر روی فرکانس فکر و پریشانی

Cognitive theories of obsessions highlight appraisals of personal significance and thought suppression in the development and maintenance of intrusive thoughts. The current study examined the role of personal significance within the context of a thought suppression paradigm. The primary aim was to examine whether suppression would have differential effects for target thoughts appraised as personally meaningful versus relatively unimportant. A blasphemous thought served as the target thought, and highly religious and nonreligious participants were recruited. Participants completed a two-interval thought suppression task; during interval 1 they were randomly assigned to suppress or not suppress the target thought and during interval 2, all participants were given “do not suppress” instructions. Suppression resulted in sustained frequency of thoughts in contrast to the decline in thought frequency observed for non-suppression. Differential effects of suppression were found across the two groups. Moreover, suppression was associated with increased negative mood and anxiety. Results suggest that suppression of personally meaningful thoughts is a counterproductive strategy.

Obsessions are recurrent, unwanted, intrusive ideation that evoke substantial distress and typically motivate active efforts to resist or otherwise control the thoughts. While obsessions per se are unique to obsessive–compulsive disorder (OCD), most people experience unwanted intrusive thoughts from time to time without significant distress. The content of these thoughts can be similar to that observed in obsessions (Rachman and de Silva, 1978 and Salkovskis and Harrison, 1984), although recent studies have suggested the overlap may not be as great as previously thought (Rassin et al., 2007 and Rassin and Muris, 2007). Recently proposed cognitive theories of OCD focus on the role of metacognition in the maintenance of obsessions (Rachman, 1997, Rachman, 1998, Salkovskis, 1985 and Salkovskis et al., 1998). Metacognition refers to cognition about thoughts: appraisals of the occurrence of thoughts, beliefs about the importance and personal significance of thought content, and efforts to control thoughts. Cognitive theories posit that appraisals about the significance of unwanted intrusive thoughts are pivotal in transforming normally occurring unwanted intrusive thoughts into obsessions that recur and provoke distress. In Rachman, 1997 and Rachman, 1998 well-articulated view, for example, only those unwanted thoughts that are appraised as personally meaningful and significant will provoke anxiety and a desire to resist or control the thoughts. He further argues that trying to control unwanted thoughts is a maladaptive strategy that paradoxically contributes to recurrence of the unwanted thoughts. Such recurrence, in turn, is likely to make the unwanted thoughts seem even more important and personally meaningful. In sum, Rachman proposes a dynamic model whereby appraisals of unwanted thoughts as important and personally relevant, combined with active resistance of such thoughts, leads to a vicious cycle of anxiety, resistance, and escalating frequency of intrusive thoughts. Consistent with cognitive theories, appraisals of intrusive thoughts (e.g., as important to control) correlate with obsessive–compulsive symptoms in clinical (Morillo et al., 2007, Obsessive Compulsive Cognitions Working Group, 2001, Obsessive Compulsive Cognitions Working Group, 2003 and Obsessive Compulsive Cognitions Working Group, 2005) and nonclinical samples (Clark and Claybourn, 1997, Freeston et al., 1992, Purdon and Clark, 1994a and Purdon and Clark, 1994b). In their classic study on thought suppression, Wegner, Schneider, Carter, and White (1987) demonstrated that participants who were instructed to suppress thoughts of a white bear ironically experienced the thought more frequently than did participants who were instructed to express the same thought. Although the findings have been mixed, a meta-analysis of 44 thought suppression studies reported a small to moderate rebound effect (estimated d = .30) in which suppressed thoughts subsequently recur more frequently than if they had not been suppressed ( Abramowitz, Tolin, & Street, 2001). Even among studies that fail to show a rebound effect, however, thought suppression appears to interfere with a natural decline in thought frequency that occurs over time when participants do not suppress their thoughts ( Belloch et al., 2004 and Purdon and Clark, 2001). Investigators interested in understanding obsessions have turned their attention to research on ironic effects of thought suppression, extending the paradigm developed by Wegner's group in ways that make it more relevant to OCD. One extension involves examining suppression of a target thought that has idiosyncratic relevance to the individual participants, which more closely approximates the kinds of intrusive thoughts found in OCD. Some evidence indicates the paradoxical effects of suppression extend to personally relevant thoughts (McNally and Ricciardi, 1996, Salkovskis and Campbell, 1994 and Trinder and Salkovskis, 1994), while other studies suggest that suppression interferes with a natural decrease in thought frequency (Belloch et al., 2004 and Purdon and Clark, 2001). However, these findings are not consistent, with some studies reporting no such ironic effects of suppression (Kelly and Kahn, 1994 and Rutledge, 1998). A second extension involves examining thought suppression in individuals with OCD, and in general, these studies have failed to show exaggerated effects of suppressing personally relevant thoughts or obsessions, as might have been expected (Janeck and Calamari, 1999 and Purdon et al., 2005). Methodological differences may account for these discrepant findings. One challenge associated with studying suppression of personally relevant thoughts, particularly obsessions, involves participants' prior experience with such idiosyncratic thoughts. Tolin, Abramowitz, Przeworski, and Foa (2002) note that individuals with OCD develop elaborate strategies to resist their unwanted thoughts, which may impact results in a short-term laboratory-based thought suppression study. OCD patients may also actively resist their own obsessions in the context of a thought suppression study even when instructed not to suppress their thoughts. Indeed, many individuals with OCD have difficulty allowing their obsessions to occur without active resistance because of the degree of distress the obsessions provoke. Therefore, Tolin et al. caution that prior personal experience with unwanted thoughts, even among nonclinical participants, may impact the results of laboratory studies of thought suppression. Other differences between personally relevant and novel target thoughts may also be relevant for understanding thought suppression. In addition to habitual strategies participants may have developed for responding to unwanted thoughts (e.g., suppression, distraction), target thoughts selected by participants may be more personally salient, provoke more distress, or occur more frequently in the participant's normal life. Most studies that have compared the suppression of idiosyncratic thoughts with neutral thoughts have failed to control for differences in valence and novelty of the thoughts in these two categories. Accordingly, the purpose of the current study was to examine several key tenets of Rachman's cognitive theory of obsessions, while controlling for variables not considered in prior thought suppression studies. One aim of this study was to investigate whether, in keeping with Rachman's theory, suppression of a personally meaningful thought would be associated with an increased frequency of thoughts. Specifically, the study was designed to examine whether the effects of thought suppression would vary as a function of the personal meaning or significance of the target thought, while attempting to control for novelty of the thought. To examine the role of personal meaning of the thought, two groups of participants were selected based on the expectation that they would differ in their appraisals of the target thought. The target thought for the suppression task was a specific blasphemous thought, and participants recruited for the two groups differed in the degree to which religion was important to them. Highly religious participants were expected to appraise the target thought as more personally significant than were participants for whom religion was unimportant. Based on the cognitive theory of obsessions, appraisals about the personal significance of the target thought were expected to moderate the effects of thought suppression on subsequent frequency of thoughts. In addition, the current study sought to examine the effects of suppression on negative mood and anxiety. Trying, but failing, to control upsetting thoughts may generate negative affect as individuals make personally relevant appraisals about their inability to control the thought (Purdon and Clark, 1993, Purdon and Clark, 1999 and Purdon and Clark, 2001). In support of this idea, Purdon (2001) reported that undergraduates' appraisals of recurrences of their most upsetting intrusive thought during a suppression task predicted negative affect following the task. Thought recurrences appraised as indicating something negative about the self and greater likelihood of the thought coming true also predicted anxiety and discomfort ratings following thought suppression (Purdon et al., 2005). Kelly and Kahn (1994) also reported significant correlations between total frequency of target thoughts during a suppression task and appraisals of being out of control and dislike of the thought. In a vignette study, Corcoran and Woody (2008) found that frequency of occurrence of the target thought influenced normal participants' appraisals of personal significance of the thought. Therefore, the second aim of this study was to examine whether, as hypothesized by the cognitive theory of obsessions, suppression of a personally meaningful target thought would be associated with increased negative affect and anxiety.