Behavioural Brain Research 231 (2012) 289–296 Contents lists available at ScienceDirect Behavioural Brain Research j ourna l ho mepage: www.elsevier.com/locate/bbr Review Animal behavior as a conceptual framework for the study of obsessive–compulsive disorder (OCD) David Eilam a,∗,1,2 , Rama Zor a,2 , Naomi Fineberg b , Haggai Hermesh c a Department of Zoology, Tel-Aviv University, Ramat-Aviv 69978 Israel b National OCD Treatment Service, Hertfordshire Partnership NHS Foundation Trust, Queen Elizabeth II Hospital, Welwyn Garden City AL7 4HQ, UK c Adult Outpatient Department and Anxiety Disorders and Behaviour Therapy Unit, Geha Mental Health Center, Rabin Medical Center, Petach-Tiquva 49100 and Sackler Faculty of Medicine, Tel Aviv University, Ramat-Aviv, Israel a r t i c l e i n f o Article history: Received 12 April 2011 Received in revised form 29 June 2011 Accepted 29 June 2011 Available online 6 July 2011 Keywords: Rituals Compulsive behavior OCD Quinpirole Animal model Video-telemetry a b s t r a c t Research on affective disorders may benefit from the methodology of studying animal behavior, in which tools are available for qualitatively and quantitatively measuring and assessing behavior with as much sophistication and attention to detail as in the analysis of the brain. To illustrate this, we first briefly review the characteristics of obsessive–compulsive disorder (OCD), and then demonstrate how the quin- pirole rat model is used as a conceptual model in studying human OCD patients. Like the rat model, the study of OCD in humans is based on video-telemetry, whereby observable, measurable, and relatively objective characteristics of OCD behavior may be extracted. In this process, OCD rituals are defined in terms of the space in which they are executed and the movements (acts) that are performed at each loca- tion or object in this space. Accordingly, OCD behavior is conceived of as comprising three hierarchical components: (i) rituals (as defined by the patients); (ii) visits to objects/locations in the environment at which the patient stops during the ritual; and (iii) acts performed at each object/location during visits. Scoring these structural components (behavioral units) is conveniently possible with readily available tools for behavioral description and analysis, providing quantitative and qualitative measures of the OCD hallmarks of repetition and addition, as well as the reduced functionality in OCD behavior. Altogether, the concept that was developed in the context of an animal model provides a useful tool that may facilitate OCD diagnosis, assessment and treatment, and may be similarly applied for other psychiatric disorders. © 2011 Elsevier B.V. All rights reserved. Contents 1. What is OCD? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 289 2. What is the quinpirole rat model of OCD? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 290 3. Where do OCD behavior and animal behavior (ethology) intersect? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 290 4. Rituals—a functional definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 291 5. Rituals—a temporal definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 291 6. Rituals—a spatial definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 291 7. Rituals—a component definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 291 8. Repetition, addition, and reduced functionality—the hallmarks of OCD behavior . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 293 9. The advantage of applying video-telemetry for OCD rituals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 294 10. The potential of video-telemetry application for other psychiatric disorders . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 295 Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 295 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 295 ∗ Corresponding author. Tel.: +972 3 6406471, fax: +972 3 6409403. E-mail address: eilam@post.tau.ac.il (D. Eilam). 1 David Eilam is a visiting Professor at the Department of OTANES, University of South Africa. 2 These authors contributed equally to all the phases of this study. 1. What is OCD? Obsessive–compulsive disorder (OCD) is a severe disabling psy- chiatric affliction with a strong impact on life quality [1]. It was recognized as early as the 16th century, and is now known to have a prevalence rate of 1–3%, which is almost twice that of schizophrenia 0166-4328/$ – see front matter © 2011 Elsevier B.V. All rights reserved. doi:10.1016/j.bbr.2011.06.033