Global study finds 250 genes linked to OCD

Researchers say they have found the genes linked to obsessive compulsive disorder (OCD), after identifying 30 regions on the human genome associated with this debilitating yet often misunderstood mental health condition. Their study, which involved over 200 investigators around the world, has been published in the journal Nature Genetics.

OCD is often categorised as an obsession with cleaning or checking. However, it can take many forms, including worrying about harming others, doubts about relationships, existential worries, inappropriate sexual thoughts or persistent concern about responsibilities.

“People who suffer from OCD are driven by a fear they’ve done something wrong, or that they’re going to do something wrong,” explained clinical psychologist and OCD specialist Dr Emily O’Leary. “They worry they could hurt their loved ones or themselves. For people with OCD, it’s like being trapped in their own worst nightmare.”

The new study is the culmination of more than 20 years of sample collection. It involved more than 50,000 people with OCD and 2 million people who did not have OCD, and pinpointed approximately 250 genes linked to OCD. These genes were found to be most active in three key brain areas — the hippocampus, the striatum and the cerebral cortex — which aligns with previous neuroscience studies.

“This is the first study where we found actual genes that play a role in OCD, which is really exciting,” said Professor Eske Derks, senior group leader of the Translational Neurogenomics Laboratory at QIMR Berghofer, who co-supervised the study. “We’ve been working on this for many years, but these findings have dramatically increased our knowledge of the genetic basis of OCD.

“We found a really large number of genes which are shared with anxiety disorders, depression and also with anorexia nervosa. There’s a lot of overlap in the genes that cause these different mental health conditions.”

According to Derks, the next steps are to use these genetic discoveries to identify existing drugs that may be effective for OCD patients, which could pave the way for more innovative treatment options. O’Leary added that the findings offer an opportunity to speed up diagnosis and treatment.

“What happens in clinical practice is that clients will come to us typically 10–14 years after diagnosis, and by this time they are really unwell,” she said. “What this research shows us is that we can be more proactive and actually start looking at who is more likely to develop the disorder.”

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