A study in the journal “Scientific Reports” supports the theory that there may be more than one type of depression.
“It has always been speculated that different types of depression exist, and they influence the effectiveness of (antidepressant drugs),” said study co-author Kenji Doya in a press release. “But there has been no consensus.”
Doya said the research is “the first study” to pinpoint three different subsets of depression depending on a person’s brain activity and the trauma they may have experienced as a child, per the press release. And, the study says, one type doesn’t respond to medicine.
Researchers examined 134 people — half with diagnosed depression, half without — and conducted MRIs to see how different regions of a person’s brain interacted through neural pathways. Specifically, they looked at the pattern of connections in a person’s angular gyrus, a region of the brain which deals with memory, spatial cognition, language and numbers.
They also gave participants a questionnaire to determine the severity of childhood trauma they experienced, the study says. All were asked about sleep patterns and any mental health issues they may be struggling with at the time.
The study found three types of depression: One marked by unusual connectivity patterns in the brain but no significant childhood trauma, one marked by significant childhood trauma but no unusual connectivity patterns in the brain, and one marked by both .
Selective Serotonin Reuptake Inhibitors, a common antidepressant medication that attempts to boost the amount of serotonin in the brain, worked on the first two types of depression found in some subjects — but didn’t help alleviate symptoms associated with the third, the study noted.
For Doya, this discovery could help improve medication in the future for those with depression.
“It provides scientists studying neurobiological aspects of depression a promising direction in which to pursue their research,” he said in the press release.
The Centers for Disease Control and Prevention estimates that 16 million Americans have depression in any given year — and one out of every 6 people in the U.S. will grapple with a depressive episode at least once in their life.
Another study in the journal “Translational Psychiatry” purported to find a gene that could contribute to seasonal affective disorder, another possible type of depression that usually flares up when the days get shorter and the temperature gets colder.
“A substantial minority of people with mood disorders do have depression that is seasonal,” said study author James Bennett Potash , according to PsyPost. “We have known this for awhile now and our study supports it.”