Depression may be More than Just Sadness

By Corinna Underwood
October 27, 2006

A team of New York scientists has found that clinically depressed people may have abnormalities in a region of the brain that regulates pleasure and reward - and the finding could ultimately lead to novel ways to treat the disease.

Dr. David Silbersweig and his colleagues at Weill Cornell Medical Center brought 22 people into the research laboratory to undergo brain scans while watching words come up on a monitor. Some words were positive, some negative and others neutral. The aim was to see if the depressed brain looked different in the region that governs reward when reading these words.

The results show that indeed it does. The scientists tested 10 depressed people who had not yet received treatment and 12 volunteers with no history of mental illness. One key characteristic of depression is that patients have a very hard time motivating themselves and enjoying things that once made them feel good. The brain scan measured blood oxygen changes in active brain regions. The color-coded statistical images allowed the researchers to determine which areas were most active in response to emotion-laden words.

The scientists found that the brains of non-depressed volunteers responded differently to positive and negative words, particularly in an area called the ventral striatum, a key reward center of the brain. Positive words like ‘rejoice’ and ’success’ triggered more activity in this region than negative words like ‘damaged’ and ‘useless’ or the neutral words. By comparison, those with depression had decreased activity in this brain region when reading the positive words. Silbersweig said that this finding, published in the latest issue of the American Journal of Psychiatry, suggests that the reward area is not reacting to positive stimuli in depressed people. The team also identified another region that differed in those diagnosed with depression: an area in the front of the brain that regulates self-awareness of emotion.