Finding a biomarker could help break cycle of depression

Depression is, unfortunately, often a lifelong commitment. Cycles of recovery and relapse can devastate patients and their families as symptoms reappear after it was thought that treatment was working. And the cycle is hard to break. Every time a formerly depressed person relapses, it increases his or her chances of another relapse by 16%. This problem is prompting researchers to look for biomarkers that can predict whether a patient who has recovered from depression will relapse. Canadian researcher Norman Farb, writing in the journal Biological Psychiatry, found that when formerly depressed people experience mild states of sadness, the nature of their brains' response can predict whether they will relapse.

Here's what Farb did: He sat down 16 formerly depressed people and made them watch sad movie clips. Then he took MRI snapshots of their brain activity. Over the next year-and-a-half, 9 of them relapsed into depression. Comparing the relapsed patients' MRI to those of people who had never been depressed, Farb found that, when faced with sadness, relapsing patients showed more activity in a frontal region of the brain known as the medial prefrontal gyrus. It's an area of the brain that is also linked to a tendency to think obsessively. Those who did not relapse showed more activity in the rear part of the brain that processes visual information and is linked to greater feelings of acceptance.

"Despite achieving an apparent recovery from the symptoms of depression, this study suggests that there are important differences in how formerly depressed people respond to emotional challenges that predict future well-being," Farb said in a release. "For a person with a history of depression, using the frontal brain's ability to analyze and interpret sadness may actually be an unhealthy reaction that can perpetuate the chronic cycle of depression."

So, what can be done? For one thing, those who are identified as at risk for relapse of depression can be trained to change their way of responding to negative emotion. "Relapse is one of the most vexing problems in depression treatment," John Krystal, editor of Biological Psychiatry, said in the release. "Having a biomarker for relapse could guide a new generation of treatment research."

- read the release