Behaviour Research and Therapy 45 (2007) 2640–2651 Role of thought-related beliefs and coping strategies in the escalation of intrusive thoughts: An analog to obsessive–compulsive disorder Brook A. Marcks, Douglas W. Woods à Department of Psychology, University of Wisconsin-Milwaukee, Box 413, Milwaukee, WI 53201, USA Received 16 January 2007; received in revised form 11 June 2007; accepted 18 June 2007 Abstract Cognitive–behavioral models of obsessive–compulsive disorder (OCD) assume that obsessions have their origin in normal intrusive thoughts. These models propose that certain beliefs, such as thought–action fusion (TAF) beliefs, combined with the use of ineffective coping strategies, such as thought suppression, lead to the development of OCD. The purpose of the current study was to examine the relationship between these variables in a non-clinical sample in addition to exploring the effects of an alternative, acceptance-based coping strategy. This study explored the relationship between TAF beliefs, thought suppression, and OC-consistent symptoms via mediational analyses. Results showed that thought suppression mediated the relationship between TAF beliefs and OC-consistent symptoms. This study also experimentally examined the effects of various coping strategies (suppression, acceptance, or monitor-only) on the frequency of a distressing intrusion and appraisal ratings (e.g., anxiety, guilt, responsibility) after a TAF induction. Spontaneous suppression in the monitor-only group made comparisons of the experimental data difficult. However, analyses provided preliminary evidence suggesting that thought suppression is related to more intrusions, higher levels of anxiety, and negative appraisals, whereas an acceptance-based approach may be a useful alternative. Additional findings, limitations of the current study, and directions for future research are discussed. r 2007 Elsevier Ltd. All rights reserved. Keywords: Intrusive thoughts; Obsessive–compulsive disorder; Thought suppression; Thought–action fusion; Acceptance; Experimental psychopathology Introduction Research suggests that 80–99% of persons in non-clinical samples experience intrusive thoughts (Freeston, Ladouceur, Thibodeau, & Gagnon, 1991; Purdon & Clark, 1993). Such thoughts are believed to play a role in the development and maintenance of a number of disorders including post-traumatic stress disorder and obsessive–compulsive disorder (OCD) (Ladouceur et al., 2000). There are many similarities between obsessions and intrusive thoughts in those without OCD. Both are similar in form, appraised negatively, ARTICLE IN PRESS www.elsevier.com/locate/brat 0005-7967/$ - see front matter r 2007 Elsevier Ltd. All rights reserved. doi:10.1016/j.brat.2007.06.012 à Corresponding author. Tel.: +1 414 229 5335; fax: +1 414 229 5219. E-mail address: dwoods@uwm.edu (D.W. Woods).