The characteristics of unacceptable/taboo thoughts in obsessive–compulsive disorder Vlasios Brakoulias a, ⁎ , Vladan Starcevic a , David Berle b , Denise Milicevic b , Karen Moses b , Anthony Hannan b , Peter Sammut c , Andrew Martin d a University of Sydney, Sydney Medical School-Nepean, Discipline of Psychiatry, Sydney/Penrith, NSW, Australia b Nepean Anxiety Disorders Clinic, Nepean/Blue Mountains Local Health District, Penrith, NSW, Australia c Nepean Hospital, Department of Psychiatry, Penrith, NSW, Australia d NHMRC Clinical Trials Centre, University of Sydney, Sydney, NSW, Australia Abstract Background: In the quest to unravel the heterogeneity of obsessive–compulsive disorder (OCD), an increasing number of factor analytic studies are recognising unacceptable/taboo thoughts as one of the symptom dimensions of OCD. Aims: This study aims to examine the characteristics associated with unacceptable/taboo thoughts. Methods: Using the Yale–Brown Obsessive–Compulsive Scale Symptom Checklist (YBOCS-SC) with 154 individuals with OCD, obsessive–compulsive symptoms were subjected to principal components analysis. The characteristics associated with the resulting symptom dimensions were then assessed using logistic and linear regression techniques. Results: Unacceptable/taboo thoughts comprised of sexual, religious and impulsive aggressive obsessions, and mental rituals. Higher scores on an unacceptable/taboo thoughts symptom dimension were predicted by higher Y-BOCS obsession subscores, Y-BOCS time preoccupied by obsessions scores, Y-BOCS distress due to obsessions scores, importance of control of thought ratings, male gender, and having had treatment prior to entering into the study. Unacceptable/taboo thoughts were also predicted by greater levels of hostility, and a past history of non-alcohol substance dependence. Conclusions: An unacceptable/taboo thought symptom dimension of OCD is supported by a unique set of associated characteristics that should be considered in the assessment and treatment of individuals with these symptoms. Crown Copyright © 2013 Published by Elsevier Inc. All rights reserved. 1. Introduction Unacceptable/taboo thoughts, also known as “pure obsessions”, refer to impulsive aggressive, sexual and religious obsessions. The observation that some obsessions occurred in the apparent absence of compulsions was first made by Baer [1] in a study employing factor analysis techniques. Since then, there have been a number of factor analytic studies [2–9] that have revealed a symptom dimension of obsessive–compulsive disorder (OCD) char- acterised predominantly by obsessions and in particular aggressive, sexual and religious obsessions. More recently, studies [10,11] have demonstrated that “pure obsessions” is a misnomer in that unacceptable/taboo thoughts tend to be accompanied by compulsions. Unacceptable/taboo thoughts are distinctly ego-dystonic with a repugnant quality that tends not to be so prominent in other OCD symptoms [12]. As their name suggests, the content of these obsessions typically involves unacceptable, taboo or forbidden themes such as stabbing a relative, incest or blasphemy. Studies have associated unacceptable/ taboo thoughts with mental rituals [10], reassurance- seeking [6,10], avoidance [13,14], good insight [15], male gender [16,17], and being more likely to seek professional help [18]. Available online at www.sciencedirect.com Comprehensive Psychiatry xx (2013) xxx – xxx www.elsevier.com/locate/comppsych No conflicts of interest. This study was funded by the Nepean Medical Research foundation, a competitive Pfizer Neuroscience Grant and a grant from the Discipline of Psychiatry at The University of Sydney. ⁎ Corresponding author. Nepean Hospital, Department of Psychiatry, PO Box 63, Penrith, NSW 2751, Australia. Tel.: +61 2 4734 2585; fax: +61 2 4734 3343. E-mail addresses: vbrakoulias@bigpond.com, vlasios.brakoulias@sydney.edu.au (V. Brakoulias). 0010-440X/$ – see front matter. Crown Copyright © 2013 Published by Elsevier Inc. All rights reserved. http://dx.doi.org/10.1016/j.comppsych.2013.02.005