OCD Genetic Link Discovery Raises Hope of Precision Treatment for Debilitating Disease

Obsessive-compulsive disorder (OCD) is a debilitating condition that causes irrational fixations. Sufferers speak about the mental torment of strange, intrusive thoughts that cripple their lives—issues far worse than the stereotypical image of a person checking the door lock several times before finally leaving the house. 

Although treatments exist, most are limited to reducing the symptoms. Now, after decades of research during which the cause of OCD has remained a mystery, there are finally some leads. 

A team of scientists for the first time says it’s identified the genes that are responsible for OCD. The findings, published Tuesday in Nature Communications, may help scientists develop more precise and effective treatments for the psychiatric condition.

To home in on potential genetic links to OCD, the scientists identified 608 genes in humans, dogs and mice that they suspected could be involved. They compared genetics of 592 cases of OCD to 560 healthy controls of animals and humans. Although dogs may not be like humans in lining up things neatly on a shelf or washing their hands 50 times a day, some are more prone to repetitive and obsessive behaviors such as incessantly chasing their tail or self-mutilation through nonstop licking. So the researchers wanted to take a closer look at the genes in these animals as well.

Through their analysis of human and animal genomes, the researchers found four genes—NRXN1, HTR2A, CTTNBP2 and REEP3—strongly linked with OCD. Two of the genes discovered to have mutations in people with OCD are associated with the brain’s ability to control action. The genes are also responsible for the production of serotonin, a chemical in the body that acts as a neurotransmitter and is involved in regulating a person’s mood. Some research suggest that low levels of serotonin production may cause OCD.

“In a modest-size cohort of OCD cases and controls we find associations driven by both coding and regulatory variants, highlighting new potential therapeutic targets,” the researchers write in their study. “Our method holds promise for elucidating the biological basis of complex disease, and for extending the power of precision medicine to previously excluded populations.”

Millions of people worldwide suffer from OCD. According to the National Alliance on Mental Illness, more than 2 percent of adults in the U.S. (nearly 1 in 40 people) will be diagnosed with OCD during their lives. The condition is also equally prevalent in children.  

Treatment for OCD is still severely limited. Many patients try cognitive behavioral therapy (CBT), a type of psychological counseling that focuses on behavior modification. Some doctors prescribe SSRIs or other psychiatric drugs to help manage the condition, and because severe OCD is often coupled with other mental disorders such as depression and anxiety.

The findings from this new study may provide a way to treat OCD. Researchers hope the work will lead to drugs that target pathways linked to these specific genes. It may also be possible to correct the condition through gene-editing that removes and replaces the faulty DNA that causes the condition.

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