For a lay person a mental health condition is a mental health condition. PTSD is PTSD. Depression is depression. However, mental health conditions come in subtypes which have different characteristics. They may require different forms of treatment as well. In this regard, researchers at Stanford University have identified a new depression subtype. The goal of their work is to make diagnosis more precise and treatment more effective.
Why Don’t All Depressed Patients Respond the Same to Treatment?
Roughly a fourth of depressed patients do not respond to treatment with standard antidepressants. Doctors at Stanford found that twenty-seven percent of depressed patients had difficulty planning ahead, sustaining focus in the face of distractions, maintaining self-control and suppressing inappropriate behavior. These were the ones whose depression did not get better with the usual medicines. Brain imaging with these patients showed reduced activity in the two brain regions that handle those tasks.
Breaking Down Depression into Subtypes
Depression is considered to be a mood disorder. Today’s most commonly used antidepressants are selective serotonin reuptake inhibitors (SSRIs). They modify the levels and activity of the substance serotonin in the brain and thus help the majority of people with depression. What the researchers found was that a subset of people, about a fourth, have cognitive dysfunctions and their depression does not get better with SSRIs. It turns out that other (non-SSRI) antidepressants work better in this subtype of depression.
Making Diagnosis of Depression Subtypes More Accurate
Up to this point doctors treating depressed patients have used the drugs that tend to work the best in the most people, SSRIs, and only try other and commonly older medicines when the first line of treatment does not work. Researchers are looking for ways to avoid this trial and error approach so that all depressed patients can get the most effective therapy for them right away. By adding brain imaging to the diagnostic process doctors hope to be able to start depressed patients on the best medicine for them from the very start.
How the Depression Study Worked
Researchers studied one thousand eight depressed patients who had a diagnosis of depression and had never received treatment before. They were randomly selected to receive one of three antidepressant medications. These were escitalopram and sertraline (Lexapro and Zoloft) which both act on serotonin and venlafaxine-XR (Effexor) which acts on serotonin and norepinephrine. The study lasted eight weeks and seven hundred twelve people completed the study.
Measuring Depression Treatment Results
People in the study filled out a self-assessment of their depression before and after the study. Clinicians examined each person before and after and also assessed levels of depression. In addition, measures of function at work an in social settings were also evaluated before and after treatment.
What was different in this study of depression compared to other studies was that people also had cognitive tests that measured working memory, decision speed, sustained attention, and verbal memory before and after treatment. Ninety-six of the study participants underwent functional magnetic resonance imaging while completing a task in which they pressed a button in response to a visual cue.
Depression Study Results
From the participants of the study, researchers found that twenty-seven percent had impaired cognitive functioning on behavioral tests as well as reduced activity in specific areas of their brains on their brain scans. Researchers called this constellation of findings the cognitive biotype. What they found was that people in this depression subtype had a substantially poorer response to the antidepressant medications used in the study. They are currently following up with a study of a different antidepressant, guanfacine for treatment of this subgroup. Up to this point psychedelic medicines have not been used as part of any of their treatment protocols.