Researchers have found three more subtypes of depression. This study was published in the journal Scientific Reports and it aims to focus on why some types of depression don’t respond to certain medications.
According to new demographic data, it has been noted that about 16 million people in the United States suffer from depression and about 300 million people around the world face one or more kinds of depression at any given time.
Out of the 16 million people, at least 60% individuals face severe impairment and as a result, up to 30% of those people do not find any kind of relief from the medications given by their psychiatrists.
SSRIs (short of Selective serotonin reuptake inhibitors) are still of the one commonly prescribed medicines for the treatment of depression. Their use help to increase the levels of serotonin. Serotonin is a hormone that induces happiness and hence is commonly known as the ‘happiness hormone.’
This new research may help to explain why SSRIs are still unable to tackle all kinds of depression. Prof. Kenji Doya, of the Neural Computation Unit at the Okinawa Institute of Science and Technology Graduate University (OIST) in Japan and his team have now successfully determined three new subtypes of depression using various types of brain imaging techniques.
Mapping the Brain in Depression
Professor Doya expressed his concerns about the working of SSRIs saying he always knew there had been many different forms of depression due to which these medications were able to treat only a few kinds of depression. But as there had been no consensus about the types of depression, he had to do the research himself to prove his theory.
The team analyzed the data if 134 study participants, half of which were already diagnosed with depression by other doctors. The investigators used various methods like questionnaires and blood tests to collect information of the participants including sleep patterns, life histories, and other mental illnesses.
MRI scanners were also used to study the participants’ brain activity. This enabled them to map 78 various regions of the brain and then examine the connections between them.
The author of the study said that his biggest challenge in the study was to invent ways through which the information could be extracted and the relevant data be separated from the rest. As the information gained from MRI was immense, the authors had to work days and nights to cluster similar data together.
Various statisticians were finally able to develop a new method that allowed the researchers to break down more than 3,000 measurable features into groups of five data clusters. These measurable features included two main events: the incidence of childhood trauma and the first depressive episode.
Drug-resistant Subtype of Depression
Three out of those five data clusters were found as different subtypes of depression. The brain imaging showed that the areas which were connected to angular gyrus were the key factors that predicted whether or not SSRIs effectively treat a depressed person. The functional connectivity of various brain areas proved a vital part in concluding this result.
The angular gyrus is an area of the brain that controls important processes like language perception, concentration, and spatial cognition. The study also found that one of the subtypes- that didn’t respond to the unrivaled SSRIs- was connected to childhood trauma.
The other two subtypes of depressions responded well to various drugs and were unaffected by childhood trauma. These subtypes also had low brain connectivity.
The most useful aspect of this research is that it will allow other researchers to pursue a promising direction and make more detailed results.