Three sub-types of depression have been identified for the first time, new research reveals.
One type does not respond to SSRI antidepressants, the most common treatment for depression.
The type that does not respond to antidepressants exists in people with experience of childhood trauma, along with certain patterns of brain activity.
SSRIs are thought to work by boosting levels of serotonin in the brain, but they do not work on some people.
Professor Kenji Doya, study co-author, said:
“It has always been speculated that different types of depression exist, and they influence the effectiveness of the drug.
But there has been no consensus.”
For the study, 134 people had blood tests, completed a series of questionnaires and had brain scans.
The results revealed three different sub-types, Professor Doya said:
“This is the first study to identify depression sub-types from life history and MRI data.”
Two of the sub-types were linked to successfully responding to antidepressants.
People with these two type of depression had not suffered childhood trauma and did not have unusually high levels of connectivity between different areas of the brain.
The third type, that does not respond to antidepressants, is linked to unusual activity in the angular gyrus, a brain structure critical for processing language, attention and other areas of cognition.
It is hoped that understanding depression sub-types will aid its treatment.
Dr. Tomoki Tokuda, the study’s lead author, said:
“The major challenge in this study was to develop a statistical tool that could extract relevant information for clustering similar subjects together.”
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The study was published in the journal Scientific Reports (Tokuda et al., 2018).