Twin Research and Human Genetics

Articles

Twin Studies on Obsessive–Compulsive Disorder: A Review

Daniël S. van Grootheesta1 c1, Daniëlle C. Catha2, Aartjan T. Beekmana3 and Dorret I. Boomsmaa4

a1 Department of Biological Psychology, Vrije Universiteit Amsterdam, Amsterdam, the Netherlands; Department of Psychiatry, Vrije Universiteit Amsterdam, Amsterdam, the Netherlands. Ds.van.grootheest@psy.vu.nl

a2 Department of Psychiatry, Vrije Universiteit Amsterdam, Amsterdam, the Netherlands.

a3 Department of Psychiatry, Vrije Universiteit Amsterdam, Amsterdam, the Netherlands.

a4 Department of Biological Psychology, Vrije Universiteit Amsterdam, Amsterdam, the Netherlands.

Abstract

Genetic factors have historically been thought of as important in the development of obsessive–compulsive disorder (OCD). For the estimation of the relative importance of genetic and environmental factors, twin studies are an obvious approach. Twin studies of OCD have a long history, starting in 1929. In this review, over 70 years of twin research of OCD is presented, using four different approaches that represent the steps in the twin research of OCD from past to present. These steps include (1) case-studies of twins with OCD from the old literature; (2) twin studies of OCD using Diagnostic and Statistical Manual of Mental Disorders (DSM) criteria; (3) twin studies of OCD using a dimensional approach, comparing resemblances in monozygotic and dizygotic twins; and (4) twin studies of OCD using a dimensional approach, analyzing the data with Structural Equation Modeling. It is concluded that only the studies using the last method have convincingly shown that, in children, obsessive–compulsive (OC) symptoms are heritable, with genetic influences in the range of 45% to 65%. In adults, studies are suggestive for a genetic influence on OC symptoms, ranging from 27% to 47%, but a large twin study using a bio- metrical approach with continuous data is still needed to provide conclusive evidence. Strategies for future twin studies of OCD are discussed.

(Received May 24 2005)

(Accepted June 01 2005)

Correspondence:

c1 Address for correspondence: Daniël van Grootheest, Vrije Universiteit, Department of Biological Psychology, Van der Boechorststraat 1, 1081 BT Amsterdam, the Netherlands.

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