Effects of selective serotonin reuptake inhibitors on thought-action fusion, metacognitions, and thought suppression in obsessive-compulsive disorder Lutfullah Besiroglu a, ⁎ , Nuralay Çetinkaya b , Yavuz Selvi a , Abdullah Atli a a Department of Psychiatry, Faculty of Medicine, Yuzuncu Yil University, Van, 65200, Turkey b Department of Psychiatry, Erzurum State Hospital, Erzurum, 25000, Turkey Abstract Objective: We aimed to assess whether cognitive processes change over time in patients with obsessive-compulsive disorder (OCD) receiving selective serotonin reuptake inhibitors without cognitive behavioral therapy and to investigate the factors associated with probable cognitive changes. Methods: During the 16 weeks of the study, 55 patients who met the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, criteria for OCD received open-label treatment with sertraline (100-200 mg/d) or fluoxetine (40-80 mg/d) and were assessed using the Yale-Brown Obsessive-Compulsive Scale, Beck Depression Inventory (BDI), Thought-Action Fusion Scale (TAFS), Metacognitions Questionnaire (MCQ-30), and White Bear Suppression Inventory (WBSI). Results: The Yale-Brown Obsessive-Compulsive Scale (P b .001), BDI (P b .001), TAFS morality (P b .005), MCQ-30 (P b .01), and WBSI (P b .005) scores at follow-up were significantly lower than baseline scores. When we excluded OCD patients with depressive disorder (n = 12), statistical significance in paired comparisons for MCQ and WBSI disappeared. Similarly, when OCD patients with religious obsessions (n = 16) were excluded, paired comparisons for MCQ and TAF morality were not statistically significant. Changes in BDI, TAFS morality, MCQ-30, and WBSI (P b .005) were significantly correlated with changes in severity of obsessions, but not that of compulsions. After controlling for the change in depression severity, significant correlations between changes in obsessive and cognitive scales did not continue to have statistical significance. The BDI changes (P b .05) significantly explained the changes in symptom severity in a linear regression model. Conclusions: Our findings suggest that selective serotonin reuptake inhibitors can change appraisals of obsessive intrusions via their effects on negative emotions. © 2011 Elsevier Inc. All rights reserved. 1. Introduction Cognitive models in obsessive-compulsive disorder (OCD) are interested in what processes and structures of the information processing system account for the persis- tence, uncontrollability, aversiveness, and idiosyncratic nature of obsessional phenomena [1]. Several researchers have explored the thought suppression theory, focusing on its role in the exacerbation of intrusive thoughts [2-4]. According to this theory, efforts at controlling thoughts may result in a paradoxical increase in thought frequency. Another cognitive theory germane to development of obsessions, described as thought-action fusion (TAF), is defined as the belief that specific intrusive thoughts can directly influence the relevant external event and/or the belief that having these intrusive thoughts is morally equivalent to carrying out a prohibited action [3,5]. Recently, metacognitive theory as the tendency to focus attention on and monitor thinking has been proposed to explain how intrusive thoughts or doubts activate metabeliefs and emotional reactions [6,7]. Although different cognitive factors have been suggested to explain the emergence and maintenance of OCD, the Available online at www.sciencedirect.com Comprehensive Psychiatry 52 (2011) 556 – 561 www.elsevier.com/locate/comppsych This research was conducted at Yuzuncu Yil University Hospital, Van, Turkey, and has not been supported by any commercial or noncommercial organization. For all authors, there is no actual or potential conflict of interest including any financial, personal, or other relationships with other people or organizations. ⁎ Corresponding author. Yüzüncü Yıl University, School of Medicine, Department of Psychiatry, Van 65200, Turkey. Tel.: +90 432 216 4711; fax: +90 432 216 7519. E-mail address: lbesiroglu@gmail.com (L. Besiroglu). 0010-440X/$ – see front matter © 2011 Elsevier Inc. All rights reserved. doi:10.1016/j.comppsych.2010.10.003