Brain hues disclose depression clues.

For poorly understood reasons, a substantial minority of people suffering from major depression remain mired in melancholy, no matter what antidepressant medication they receive. A study using brain scans now suggests that neural activity in a specific location makes or breaks drug-aided recovery from depression.

Depressed individuals who benefit from antidepressant drugs show elevated activity at the front of the cingulate gyrus, a small structure in the brain's outer layer, or cortex, contends Helen S. Mayberg, a psychiatrist at the University of Texas Health Science Center at San Antonio. In contrast, depressed folks who do not respond to antidepressants display sluggish cingulate activity, Mayberg and her coworkers find.

"If this finding holds up, it raises the possibility of using [brain-scan] results to help diagnose and treat depressed patients," Mayberg asserts.

She suspects that the cingulate gyrus is an anatomical bridge linking a number of neural pathways that malfunction in major depression. Cingulate overactivity may represent an effort to compensate for depression-inducing disturbances in those pathways, laying the groundwork for the mood-enhancing effects of antidepressants, the Texas researcher theorizes.

Mayberg's study, published in the March 3 NeuroReport, examined 18 adult volunteers diagnosed with major depression-a debilitating condition that includes extreme sadness, hopelessness, and apathy-and 15 without depression.

All participants underwent positron emission tomography (PET) scanning, which estimates cerebral energy use and reflects how hard brain cells work. The depressed people, who were not in long-term drug treatment, then received any of several antidepressants for 6 weeks. Most had not taken such drugs for at least 2 weeks; a few had begun drug treatment within days of the PET scan.

The researchers found that drugs did not change cingulate activity in either group. The only significant difference between the 10 depressed patients who responded to drugs and the 8 who did not was an excess or deficiency, respectively, of cingulate labor, compared to the nondepressed controls.

"This finding makes sense, especially for the many depressed people who experience a lot of anxiety," remarks psychiatrist Lewis Baxter of the University of Alabama at Birmingham. Other studies suggest that the cingulate gyrus coordinates anxiety regarding life-or-death threats, he says.

If Mayberg's finding holds up, cingulate gyrus overactivity may signal receptivity to all kinds of depression treatments, including psychotherapy, Baxter adds.