Brain Abnormality May Predict Depression

Structural differences in the brain appear to be linked to a greater risk of depression. In one of the largest, multi-generational brain imaging studies yet conducted, researchers at Columbia University Medical Center and the New York State Psychiatric Institute have discovered a correlation between thinning of the right hemisphere of the brain and the risk of depression. Study participants at high risk of developing depression exhibited a 28% thinning of the right cortex, the outermost surface of the brain, according an article published in the online edition of the Proceedings of the National Academy of Sciences.

The surprising loss of brain matter was similar to that experienced by people with Alzheimer’s disease and schizophrenia. “The difference was so great that at first we almost didn’t believe it,” admitted senior researcher Dr. Bradley Peterson, director of Child & Adolescent Psychiatry and director of MRI Research at the Department of Psychiatry at Columbia University Medical Center and the New York State Psychiatric Institute.

Researchers surmise that thinning of the cortex may disrupt the ability to process social and emotional cues from other people, potentially leading to depression. It’s important to note that researchers did not find a correlation between thinning on the right side of the brain and actual depression, but only to an increased risk of developing the illness. However, study participants who also exhibited thinning on the left side of the brain did develop depression or anxiety. Researchers also found that thinning of the cortex had a measurable negative impact on attention and memory. The thinner the cortex, the worse study participants did on attention and memory tests.

The biological children of depressed adults also exhibited thinner cortexes, giving credence to other studies indicating a potential genetic component to depression. Study co-leader Myrna Weissman, professor of epidemiology in psychiatry at Columbia University College of Physicians and Surgeons and director of the New York State Psychiatric Institute Division of Epidemiology, has tracked familial depression for 27 years. Now covering three generations, her study has found that depression is transmitted across generations in high risk families.

Researchers hope the study will open new avenues for diagnosing and treating depression. People with a family history of depression who exhibit thinning of the cortex may benefit from behavioral therapies that improve attention and memory and, possibly, from drugs used to treat ADHD.