Depression is a common disorder for which cognitive behavioral therapy (CBT) is the recommended treatment for most patients. Researchers at Karolinska Institutet have now studied how genetic factors relate to differences in outcome of CBT in 894 people with depression, and show for the first time how genetic risk scores is associated with CBT outcome.
“Understanding how genetic variation effects the outcome of psychological treatment can help us understand why some people don’t respond to it,” says study-leader Christian Rück, psychiatrist and senior lecturer at the Department of Clinical Neuroscience, Karolinska Institutet. “Ultimately this can lead to improved treatment options.”
All 894 participants in the study, which was published recently in the scientific journal Molecular Psychiatry, had been diagnosed with depression and had undergone a 12-week course of online CBT. Before the treatment, the researchers extracted their DNA from blood samples in order to analyze how outcomes correlated with genetic variation. This they did by comparing genetic variations in the participants with genetic risk scores for 6 different psychiatric conditions, education level and IQ.
A genetic risk score indicates how many genetic risk variants an individual has for a particular condition. Doing this, the researchers found that a higher genetic risk score for autism was associated with a poorer outcome after CBT for depression. This is the first time that genetic variation has been linked to outcomes of psychological treatment in a so-called genome-wide analysis – i.e. a study that analyses genetic variation across the entire genome.
The researchers are now aiming to substantiate their finding with new, larger studies. The study was conducted with the support of the internet psychiatry clinic of the Stockholm County Council, and the Swedish Research Council.