At least most other diseases have a clearly identifiable cause, however. Even if knowing that hasn’t helped where finding a cure is concerned, at least it provides something of a starting point.
Depression though, is amorphous. There’s no one thing that science has been able to point to in terms of causative agents, and for that reason, treatments vary wildly in their effectiveness. Sometimes they work, and sometimes, not so much. In fact, recent studies have shown that upwards of 30% of people who suffer from depression don’t find any relief at all with any of the existing treatments, which most commonly take the form of Selective Serotonin Reuptake Inhibitors (SSRIs).
The question is, why? Why do these treatments work most of the time, but inexplicably fail to produce results for everyone? A recently completed research study may hold the answer. A research team led by Professor Kenji Doya, working from the Neural Computation Unit at the Okinawa Institute of Science and Technology Graduate University has identified three distinct subtypes of depression.
Prior to this research, scientists had long suspected the presence of various forms of depression, but there was no road map to a clear consensus on the matter.
Professor Doya and team poured over every scrap of clinical data of their 134 study participants, half of whom had recently been diagnosed with depression. They relied on blood tests and questionnaires to collect more detailed information about sleep history, mental health, lifestyle choices and life stressors. These were augmented by periodic MRI scans used to study participant brain activity by mapping a total of seventy-eight different regions of each participant’s brain to examine possible connections between these areas.
Overall, the team collected more than three thousand measurable features they could use to define and classify depression, which they subsequently broke down into five data clusters. Of the five data clusters the team was left with, three of them corresponded with different subtypes of depression.
Using the collected MRIs, the team was able to predict when prescribing SSRIs would effectively treat depression. Specifically, the answer lay in the angular gyrus, a region of the brain that’s involved with attention span, spatial cognition, and language processing. When and where depression impacted this region, SSRIs proved to be an effective treatment.
The team also discovered that SSRIs were least effective against a subtype of depression triggered by childhood trauma.
The team was quick to note that they’re still in the earliest stages of their research, and that much more work is needed, but now, we are beginning to understand exactly how, why and most importantly when SSRIs are effective treatments for depression. The next step of course, will be to discover new and more effective treatments for those cases when SSRIs fail. It’s an exciting branch of study that promises to greatly expand our understanding of a condition that is still, in many ways, a deep mystery.