از افکار مزاحم تا وسواس: نقش ادراک مسئولیت برجستگی، و سرکوب افکار

Salkovskis [1985. Obsessional-compulsive problems: A cognitive-behavioural analysis. Behaviour Research and Therapy, 23, 571–583.] hypothesized that intrusive thoughts are more likely to occur if the thought is salient for the individual, triggers feelings of responsibility and if the individual attempts to suppress the thought. The relationship between these three factors (responsibility, salience, thought suppression) and frequency of intrusive thoughts as well as anxiety were examined in the present study. One hundred female college students were led to believe that a snake had escaped from the cage in which it was housed. Half of the participants were led to believe that they were responsible for the snake's escape and half were not (Responsibility/No Responsibility). Half of the participants in each Responsibility condition were instructed to suppress thoughts of snakes during a stream of consciousness exercise and half were not (Thought Suppression vs. No Thought Suppression). All participants then completed a second stream of consciousness without suppression instructions. Salience groups were determined by a median split on a measure of snake fearfulness. Participants for whom the snake was a salient stimulus and who believed that they were responsible for the snake's escape had the highest frequency of snake thoughts during the second stream of consciousness task and also experienced the highest levels of state anxiety. Findings are discussed with respect to Salkovskis' model.

Most individuals can identify with the experience of a disturbing thought entering consciousness. In fact, studies of the prevalence of intrusive thoughts in students and other non-clinical samples find that 80–99% of individuals report having experienced an intrusive thought in the last 2–4 weeks (Purdon and Clark, 1993 and Purdon and Clark, 1994). Given the ubiquity of intrusive thoughts, it has been proposed that one's experience of these thoughts can best be classified on a continuum from intrusive thoughts to abnormal obsessions (Purdon and Clark, 1994, Salkovskis, 1985 and Salkovskis, 1989). Even though intrusive thoughts are a common experience, most individuals remain on the “normal” side of the continuum, experiencing these thoughts infrequently and dismissing them quickly. However, 2–4% of the population is haunted incessantly by intrusive thoughts (Rasmussen & Eisen, 1992). If these thoughts occur frequently, disrupt functioning, and are accompanied by distress, an individual may meet diagnostic criteria for obsessive-compulsive disorder (American Psychiatric Association, 2000). Salkovskis, 1985 and Salkovskis, 1989 was one of the first to propose a comprehensive cognitive-behavioural model for understanding obsessions in general and obsessive-compulsive disorder in particular. Salkovskis' model accounts for the progression of an intrusive thought into an obsession by the interaction of three variables: an inflated perception of responsibility, neutralizing, and salience. According to Salkovskis, 1985 and Salkovskis, 1989, once an intrusive thought occurs, it must be followed by an appraisal of responsibility. That is, for individuals with OCD, obsessions are interpreted as an indication that they might be responsible for harm to themselves or others unless they take action to prevent it. Once this appraisal is made, it is hypothesized to result in an affective reaction (e.g., anxiety or depressed mood; Salkovskis, 1985). Salkovskis (1985) argues that it is the appraisal of responsibility—and not necessarily the content of the intrusive thoughts per se—that results in a negative affective reaction. This affective reaction is sufficiently negative to produce attempts at avoidance, accomplished in this case through attempts to neutralize the thought. Within this model, neutralizing is defined as “voluntarily initiated activity which is intended to have the effect of reducing the perceived responsibility and can be overt or covert (compulsive behaviour or thought rituals).” (Salkovskis, 1989, p. 678). This attempted neutralization paradoxically increases the salience of these thoughts and in turn their frequency. This cycle continues to increase the frequency of intrusive thoughts until they become obsessions (Salkovskis, 1985). The focus of the present study was to identify the roles of perceptions of responsibility, salience, and thought suppression in the development of an intrusive thought into an abnormal obsession. Although there have been few direct test of Salkovskis' model, several lines of evidence exist to support the role of the above-mentioned variables in the development of obsessions.

Participants were required to meet two inclusion criteria to be included in the study. First, all participants were required to believe the snake had escaped from its cage (rating of at least a 1 on a “belief” scale of 0–4). The average rating of the 100 participants who met this criterion was M = 2.31; SD = 1.30. Second, participants who had been randomly assigned to the Responsibility condition were required to meet responsibility criteria to be included in the study. Participants in the Responsibility condition were included in the study if they rated their perception of being responsible for the snake's escape at least a 1 (on a scale of 0–4). The average responsibility rating for this group (M = 2.50; SD = 1.18) was significantly higher than the average rating of the No Responsibility group (M = 0.12; SD = 0.33), t (98) = 13.71, p < 0.001. Twenty-five participants were excluded from the study, because they did not meet the belief criteria. No participants were excluded because they did not meet the responsibility criteria. Results presented below are for 100 participants who met the believability and responsibility criteria. Participants who were asked to suppress thoughts of snakes at Time One (Thought Suppression) reported significantly fewer snake thoughts at Time One (Thought Suppression; M = 6.56; SD = 5.73) than the participants who were not asked to suppress (No Though Suppression; M = 10.78; SD = 10.68), t (98) = 2.46, p < 0.05. Salience and No Salience groups were formed by dividing participants at the mean of all participants' scores on the Snake Fear Questionnaire in an attempt to (1) most equally distribute participants among the conditions and (2) create Salience (high snake fearfulness) and No Salience (low snake fearfulness) groups. While the participants were equally divided into the 2 × 2 design for Responsibility and Thought Suppression (25, 25, 25, 25), the division for Salience (snake phobia) split these cells unequally. The cells and their accompanying cell sizes are presented in Table 1.