Middle Eastern Journal of Disability Studies

Abstract
Background & Objectives: Obsessive–compulsive disorder is diagnosed based on the presence of unwanted and disturbing thoughts and repetitive behaviors. One of the treatments whose effectiveness has been confirmed in psychological disorders is the treatment based on acceptance and commitment. Therefore, this research aimed to determine the efficacy of acceptance and commitment therapy on ambiguity tolerance and cognitive flexibility in people with obsessive–compulsive disorder.
Methods: The current research was quasi–experimental and employed a pretest–posttest design with a control group. The statistical population of this research included people with obsessive–compulsive symptoms residing in the vocational training and occupational therapy camp of Semnan City, Iran, in 2022. Since the number of subjects in groups in the quasi–experimental studies is at least 15 people, 30 qualified volunteers were randomly entered into the study and randomly assigned to the experimental and control groups (each group includes 15 people). The implementation method was such that after selecting the people of the sample group and before starting the treatment program, the Ambiguity Tolerance Questionnaire (McLean, 1993) and the Psychological Flexibility Questionnaire (Dennis and Vander Wal, 2010) were distributed among both groups. After that, acceptance and commitment therapy was implemented in the experimental group (in the form of 8 sessions of 90 minutes, each session once a week), and the control group was not subjected to any treatment program. In the end, the posttest was done again from both groups. Also, after the end of the research, the treatment program was implemented for the control group to maintain the ethical standards in the research. The criteria for entering the research were as follows: 1) interview based on DSM–5 criteria and also a higher than average score on Bill Brown's Obsessive Compulsive Scale (because the statistical population of this research is people with obsessive symptoms, this measurement was carried out by a specialist in the field of clinical psychology), 2) at least a diploma level of education, 3) not participating in other psychological interventions at the same time, and 4) absence of debilitating physical and mental diseases diagnosed by the researcher using a clinical interview. The criteria for leaving the research were as follows: 1) Absence of more than three sessions, 2) non–observance of group therapy rules, and 3) suffering from a physical or mental illness that did not exist before the treatment and was identified during the implementation. Data analysis was carried out in two parts: descriptive statistics and inferential statistics. At the level of descriptive statistics, frequency, percentage, mean, and standard deviation were used, and at the level of inferential statistics, covariance analysis was used. To check the normality of the data using the Kolmogorov–Smirnov test and to check the homogeneity of variances using the Levene test and also the assumption of homogeneity of the slope of the regression lines by checking the effect of the group in the pretest interactions were used in the regression model. Finally, univariate analysis of covariance was used. Also, an independent t test was used to compare the averages of age variables of two groups, and a Chi–square test was used to compare the frequency of education variables. Data analysis was done using SPSS software version 24, and the significance level of the tests was considered to be 0.05.
Results: The results of covariance analysis for all variables of ambiguity tolerance and psychological flexibility showed significant differences between the experimental and control groups in the posttest after deleting the effect of pretest (p<0.001). Also, the value of eta squared for both ambiguity tolerance and psychological flexibility indicates the effectiveness of acceptance and commitment therapy.
Conclusion: It can be said that acceptance and commitment therapy can effectively increase the tolerance of ambiguity and cognitive flexibility of people with obsessions.