An international team of scientists at the Broad Institute of MIT and Harvard and other institutions has found evidence of four genes that can be linked to obsessive-compulsive disorder (OCD). In the article, which has been published in the journal Nature Communications, experts describe their approach to isolate genes linked to this anxiety disorder and what they found as a result.
Charles Dickens or Marcel Proust suffered from it and it is believed that Nikola Tesla and Charles Darwin, too. Obsessive-compulsive disorder is a psychiatric condition characterized by recurrent and persistent thoughts, which cause fear, restlessness, apprehension or worry, and repetitive behaviors called compulsions, to mitigate such anxiety.
Thus, people who have it tend to repeat compulsive behaviors because their brain tells them that something has not been adequately resolved and they experience the urgency of solving a problem, such as washing their hands again.
There is no cure for the disease, although recent studies have shown that, in some cases, the use of drugs that increase serotonin levels may help. Previous research has also shown that OCD is likely to be a hereditary condition and in this regard scientists focused the current study finding the genes that are likely to cause the disorder.
The study consisted in first obtaining genetic samples of 592 people diagnosed with OCD and 560 healthy people, as a control group. Genetic samples of dogs suffering from the canine form of this disorder were also included.
With all of these samples, the researchers focused on 600 specific genes possibly related to OCD and, in some cases, to autism, as many people with autism spectrum disorder have repetitive behaviors. After careful analysis, scientists isolated four genes that were different in people with OCD (previously identified as important in creating brain circuits involved in the building of links between the thalamus, striatum and cortex regions).
This is a remarkable finding, as the striatum of the brain plays a key role in learning and also in the transmission of messages from the thalamus to the cerebral cortex.
The researchers suggest that the 4 mutated genes could cause higher or lower levels of normal serotonin levels, which in turn could lead to disruption of information as interpreted by the brain, causing an abnormality in this brain circuit.
One of the genes identified (specifically the HTR2A gene) encodes a receptor for serotonin, a neurotransmitter linked to the development of certain disorders such as anxiety, stress, certain phobias and depression.
This imbalance in the serotonergic regulation of obsessive-compulsive disorder could explain the benefits obtained in 60% of patients who have been treated with antidepressants (because the drug increases serotonin levels in the body).