Leading models of obsessive-compulsive disorder (OCD) implicate thought suppression as a key factor in the escalation and persistence of the disorder. This experiment examined the effects of suppression on the frequency of obsessional thoughts in 50 individuals with a primary diagnosis of OCD, and also investigated the effects of participants’ appraisals regarding their failures in thought control on distress about intrusive thoughts and on mood. Participants’ most upsetting obsessional thought was primed and they then monitored its occurrence over two 4-min intervals. In the first interval, half of the participants were instructed to suppress their obsessional thought and half were instructed not to suppress any thoughts. In the second interval, all participants were given the ‘Do Not Suppress’ instructions. Participants rated their suppression effort and discomfort over thought occurrences after each interval and recorded their appraisals of thought recurrences during the first interval. Mood state was then reassessed. No ironic effect of suppression on frequency was noted. However, negative appraisals of thought recurrences were associated with more discomfort over thought occurrences and more negative mood at Time 2. These findings suggest that interpretations regarding failures in thought control may be of central importance in understanding obsessional problems.
3.1. Preliminary analyses
Sale scores for the sample across experimental group are presented in Table 1. Differences between experimental groups were nonsignificant at a p<0.05 level for the following measures: Y-BOCS obsessions, t(1, 47)=−0.363, p=0.72; Y-BOCS compulsions; t(1, 47)=−0.13, p=0.90; Y-BOCS total scores, t(1, 47)=−0.28, p=0.78, III scores, Pillai’s trace F(2, 46)=1.07, p=0.37; and Time 1 mood, t(1, 47)=−1.10, p=0.28. The III scale scores were within the range reported for clinical samples of individuals with OCD in large-scale psychometric studies ( Obsessive Compulsive Cognitions Working Group, 1997 and Obsessive Compulsive Cognitions Working Group, 2001). Participants in the Do Not Suppress group were older than those in the Suppress group, with differences approaching significance (M=36.29 for the Do Not Suppress group and M=30.96 for the Suppress group), t(1, 47)=−2.01, p<0.052, and males were underrepresented in the Suppress group (n=20 females, n=6 males) but not in the Do Not Suppress group (n=11 females, n=13 males), , p<0.04. There was no reason to expect that either age or sex would have any impact on the dependent variables. However, all analyses reported below were conducted with sex and age entered as covariates. None of the findings reported below changed; that is, all significant findings reported below remained significant exactly as reported, and no other findings emerged as significant that were not significant in the analyses below. As such, all analyses reported below did not include age or sex as factors. Prior to completing each statistical analysis, the data were screened for univariate and multivariate outliers. None were found unless reported otherwise.
