First Genome Study of Obsessive Compulsive Disorder Begins to Reveal Hereditary Causes of OCD

BOSTON (Aug 14, 2012) — It has long been thought that obsessive compulsive disorder (OCD) is due to a combination of both genetic and environmental causes. A new study has made significant progress in determining which of the approximately 22,000 human genes may predispose individuals to OCD.

Today the Nature Publishing Group journal Molecular Psychiatry released the results of the first genome-wide association study (GWAS) of OCD. The results are intriguing, and although the research is still in its early stages, this work helps to provide a more complete understanding of the genetics behind this debilitating disorder.

“This research helps to narrow the focus on the likely genes involved,” explains Jeff Szymanski, PhD, executive director of the International OCD Foundation (IOCDF). “In addition, these new findings could have future implications for more effective treatments of OCD, especially for those who have not had success with current medications.”

OCD is defined by the presence of recurrent thoughts and behaviors that are distressing, time consuming, or that significantly impair an individual’s day-to-day functioning. In their search for genetic factors associated with OCD, S. Evelyn Stewart, MD and her colleagues conducted the first GWAS of OCD. This was conducted by examining approximately a half million locations along the DNA of over two thousand OCD-affected individuals to look for differences compared to the DNA of control samples.

“What makes this study such a landmark for OCD is the fact that by completing a GWAS genetic research on OCD has now entered the same realm of research as the other major psychiatric disorders, such as schizophrenia, autism, and bipolar disorder,” describes Dr Stewart.

This was a large international study conducted by combining samples from over 20 sites in North and South America, Europe, and Africa. Dr. Stewart added, “The successful completion of this project by the IOCDF Genetics Collaborative demonstrates that international researchers are willing and able to combine their efforts, rather than compete against each other to learn more about the genetics behind OCD.”

An abstract of the article may be viewed online here

About the International OCD Foundation
Founded by a group of people with OCD in 1986 the International OCD Foundation (IOCDF) is an international not-for-profit organization for people with obsessive compulsive disorder (OCD) and related disorders, as well as their families and friends, and the professionals who treat OCD. The mission of the IOCDF is to educate the public and professionals about OCD in order to raise awareness and improve the quality of treatment provided; support research into the causes of and effective treatments for OCD and related disorders; improve access to resources for those with OCD and their families; and to advocate and lobby on behalf of the OCD community. For more information please visit

About the IOCDF Genetics Collaborative
The IOCDF Genetics Collaborative is a group of over 50 genetics investigators from North America, South America, Europe, and Africa and is co-chaired by S. Evelyn Stewart, PhD, Assistant Professor of Psychiatry at Harvard Medical School, and Associate Professor of Psychiatry at the University of British Columbia, and James A. Knowles, MD, PhD, Professor and Associate Chair for Research Psychiatry & The Behavioral Sciences at the Keck School of Medicine University of Southern California. Established in 2002 by the IOCDF, the Collaborative was created to allow those genetics researchers to collaborate with one another and to share their findings and DNA samples with the overall goal of identifying the genetics causes of OCD through a systematic screening of the entire human genome. There is still little known about who may be genetically predisposed to OCD and who is protected from it, though early research by the Collaborative indicates that there is an increased risk OCD in the relatives of individuals with the disorder. Learning which genes are involved will lead to a greater understanding of how OCD develops, and ultimately how to develop more effective treatments for it. For more information, visit


Contact: Carly Bourne
Director of Communications