The new research study led by Stanford Medicine published on JAMA Network1 suggests that a certain “cognitive biotype” of depression may respond poorly to standard antidepressants. 

Hold on: What’s a biotype? According to the American Psychological Association, a biotype refers to a group of individuals with a similar genetic makeup. In this case, biotype refers to people who share similar neuronal patterns when it comes to learning and processing information and regulating mood.

The research focused on those with a cognitive biotype that made them have more difficulty with planning ahead, holding concentration, and exercising self-control (as shown by brain imaging scans that measure activity in certain brain regions). The typical symptoms of depression, including trouble with executive functioning, decision-making, memory, concentration, and the ability to suppress negative emotions in favor of positive behavior, are all more pronounced in this cognitive biotype.

In the study, researchers took 1,008 adults with previously unmedicated major depressive disorder and randomly assigned each person one of three common antidepressants: escitalopram (also known as Lexapro), sertraline (Zoloft), and venlafaxine-XR (Effexor). A total of 712 participants completed the eight-week prescription.

Both before and after the antidepressant treatment, the participants’ depressive symptoms were measured using two surveys (one administered by a clinician and the other self-reported) and a cognitive assessment. 

In this assessment, participants completed a series of cognitive tasks to measure things like memory, decision speed, and attention span while an fMRI tracked their neuronal activity.