Last month (October 2017), a team of researchers from Broad Institute published a study in Nature Communication which truly delves into the biology of obsessive-compulsive disorder. They used a multispecies comparison between dogs, mice, and humans who suffer from compulsive behavior disorders, and by doing this, were able to identify new genes and biological pathways associated with OCD. The genes in question are involved in synapse maintenance and neurotransmitter signaling, suggesting potential mechanisms at work in the disorder.
Hyun Ji Noh, a postdoctoral associate who led the study, says:
“We were seeking ways to take advantage of information from other species in order to inform and focus the study in humans. Each additional species that we looked at gave us more information about possible factors in the brain that contribute to OCD.”
Using genetic associations noted in previous studies of OCD in humans, compulsive behavior in mice, and dogs with canine compulsive disorder, Noh’s team compiled an array of approximately 600 genes that appeared to have some type of connection to OCD. People with OCD often cannot stop performing compulsions, such as checking locks, cleaning, or seeking reassurance. In animals such as dogs, compulsions might involve chasing their tails or shadows for hours at a time, or not being able to stop chewing themselves.
They then designed targeted sequencing panels for these genes and examined them in more than 1,300 cases and 1,600 controls. Their hard work paid off, and the scientists were able to single out four genes expressed in the brain that appear to be involved in OCD in humans. The genes — NRXN1, HTR2A, CTTNBP2, and REEP3, — had variants in either protein-coding or regulatory DNA significantly associated with human OCD. According to the researchers, those associations could provide potential leads in terms of treatment options for OCD, especially since the mechanisms behind the condition so far have been elusive. These gene variants disrupt synapse development and also interfere with neural pathways in an area of the brain knows as the cortico-striatal loop, affecting serotonin and glutamate, two terms which are familiar to many with OCD.
The science gets more complicated, and if interested, you can read more details here. But really, what does this actually mean for those with OCD?
Well, the more we know about OCD, the closer we might be to diagnosing it earlier as well as developing new treatment options. While not everyone with mutations in these genes will develop OCD, the researchers believe you are more likely to develop OCD if you do have these gene variations.
And so the exciting research into the mysteries of OCD goes on, and progress, albeit slowly, is being made. I always find it heartening to know there are so many people dedicated to understanding this complex disorder and working hard to help those who are suffering. Not only the research scientists, but also all the dedicated health-care professionals who help those with OCD regain their lives through exposure and response prevention (ERP) therapy.