وسواسی و تلاش برای سرکوب افکار مزاحم شخصی ناخوشایند

To explore the role of the thought enhancement and thought rebound effects in obsessionality, the relationship between obsessional symptomology and responding during and after the attempted suppression of unpleasant personal intrusive thoughts was examined. Ss first completed the Maudsley Obsessive Compulsive Inventory (MOCI) [Rachman and Hodgson, 1980]. Later, Ss indicated their most frequent intrusive thought and then completed a thought suppression protocol in which they first expressed, then suppressed, and, again, expressed that thought. Ss' scores on the MOCI were examined in relation to their pattern of responding in the suppression protocol to investigate whether Ss who were higher in obsessionality were more prone to enhancement and/or rebound effects with an unpleasant personal intrusive thought than Ss who were lower in obsessionality. The following results were obtained: (1) there was a positive relationship between obsessionality levels and thought enhancement for female Ss; (2) there was a negative relationship between obsessionality levels and thought enhancement for male Ss; and (3) there was no relationship between obsessionality levels and thought rebound. These findings suggest that the rebound effect is unrelated to obsessionality and that the enhancement effect relationship to obsessionality may be more complex than previously hypothesized.

Beginning with the experiments of Wegner et al. (1987), evidence has been accruing that attempting to suppress a thought results in an increase in the frequency of that thought once efforts at suppression cease (e.g., Clark et al., 1991 and Clark et al., 1993; Macrae et al., 1994; Wegner et al., 1991; Zeitlin et al., 1995). Generally, these studies have demonstrated that individuals who first attempt to suppress a thought, subsequently experience more instances of the thought than individuals who do not first attempt suppression; a phenomenon called the rebound effect. Although thought rebound has not been observed by all researchers (e.g., LoSchiavo and Yurak, 1995; Merckelbach et al., 1991; Muris et al., 1992; Rutledge et al., 1993, Exp. 1; Smári et al., 1994), this effect has generated a great deal of interest as a parsimonious explanation for thought preoccupation and obsessionality (e.g., Wegner, 1988 and Wegner, 1989). Other researchers, however, have focused on the role of thought enhancement during attempted suppression in the formation of preoccupations and obsessions (e.g., Lavy and van den Hout, 1990; Muris et al., 1992). Although both the rebound and enhancement effects involve the attempted suppression of a thought, the enhancement effect is observed during attempted suppression, while the rebound effect is observed after attempted suppression. Generally, studies of thought enhancement have demonstrated that individuals instructed to suppress a thought, experience more instances of the thought during the suppression attempt than individuals not instructed to suppress the thought. Like thought rebound, thought enhancement has not been found in all studies (e.g., Clark et al., 1991). Most thought suppression studies have examined the effect of suppressing experimenter-provided thoughts, however, a few recent studies have examined the effect of suppressing a person's own intrusive thought (Kelly and Kahn, 1994; Salkovskis and Campbell, 1994; Smári et al., 1995; Trinder and Salkovskis, 1994). The reasoning behind these studies is aptly described by Salkovskis and Campbell (1994)who point out that, “in order to investigate the phenomenon of thought suppression in relation to obsessional problems, it would seem most appropriate to target personally relevant and naturally occurring thoughts which Ss report that they normally attempt to suppress to some extent” (p. 2). That is, examining individuals' responses while they try to suppress their own intrusive thoughts (such as the thought of a loved one being in an automobile accident) is more appropriate to the study of obsessionality than is examining individuals' responses while they try to suppress experimenter-provided thoughts (such as the thought of a white bear). If thought enhancement and thought rebound effects are related to real-world obsession and thought preoccupation, these effects should be observed when people attempt to suppress their own personal intrusive thoughts. Evidence of an enhancement effect with negative personal intrusive thoughts has been obtained in two studies (Salkovskis and Campbell, 1994; Trinder and Salkovskis, 1994). Salkovskis and Campbell (1994)observed that Ss who attempted to suppress a negative personal intrusive thought had more instances of the thought during attempted suppression than Ss who did not attempt to suppress the thought. Similarly, Trinder and Salkovskis (1994)found that Ss who attempted to suppress a negative personal intrusive thought outside of the laboratory over a four-day period had more instances of the thought than Ss who did not attempt to suppress the thought, demonstrating that the enhancement effect is not confined to the laboratory. These findings of an enhancement effect with Ss' own unpleasant intrusive thoughts provide evidence for the hypothesis that attempted thought suppression underlies real-world thought preoccupation and obsession. In contrast with these thought enhancement findings, research has failed to provide evidence of the thought rebound effect with unpleasant personal intrusive thoughts (Kelly and Kahn, 1994; Salkovskis and Campbell, 1994; Smári et al., 1995) and with pleasant personal intrusive thoughts (Kelly and Kahn, 1994). This failure to find a rebound effect with personal intrusive thoughts is inconsistent with the hypothesis that the rebound effect underlies thought preoccupation and obsessionality. It should be emphasized, however, that none of the aforementioned studies specifically examined the relationship between thought enhancement and thought rebound effects with personal intrusive thoughts and obsessional symptomology. Therefore, these studies do not directly address the issue of if and how thought enhancement and thought rebound effects relate to obsessionality. 1.1. Thought enhancement, thought rebound, and obsessionality If it is true that enhancement and/or rebound effects are involved in the synthesis of obsession, there should be a positive relationship between those effects and obsessionality levels, that is, higher levels of enhancement and/or rebound should be associated with higher levels of obsessionality. Regarding the hypothesized relationship between obsessionality and thought enhancement, the research findings, while promising, are sparse and have been obtained from female Ss only. Smári and his colleagues at the University of Iceland have demonstrated that female Ss with higher obsessionality levels experienced less suppression (i.e., more enhancement) than females Ss with lower obsessionality levels when attempting to suppress personal unwanted thoughts (Smári et al., 1995). It should be mentioned, however, that Ss in this study who were instructed to suppress a thought had fewer instances of the thought than Ss instructed to express anything including the thought (i.e., there was no evidence of an overall enhancement effect). Nevertheless, the finding that individuals with higher obsessionality levels were less able to suppress thoughts than individuals with lower obsessionality levels is consistent with the hypothesis that enhancement plays a role in the synthesis of obsession. As for the relationship of obsessionality to thought rebound, the research findings are not only sparse, they are contradictory. Consistent with the hypothesized relationship, Smári et al. (1995) observed that female Ss with higher obsessionality levels experienced the target thought a greater percentage of time following attempted suppression than did female Ss with lower obsessionality levels (although this result was not observed for other dependent measures, including the number of target thoughts Ss indicated with “x” marks). Inconsistent with the hypothesized relationship, Rutledge et al. (1995)found that thought rebound was related to obsessionality in a direction opposite that hypothesized, that is, higher levels of rebound were observed to be associated with lower levels of obsessionality. Clearly, more work remains to be done to investigate how thought enhancement and thought rebound relate to obsessionality.