March 25 (HealthDay News) -- A thinning in the right hemisphere of the brain may be associated with a higher risk for depression, U.S. researchers report.
The study included 131 people, aged 6 to 54, including those who did and did not have a family history of depression. Brain scans revealed that those with depression in their family history had a 28 percent thinning of the right cortex, the brain's outermost surface. No thinning was seen in those with no family history of the disorder.
The degree of thinning was on par to the loss of brain matter typically seen in Alzheimer's disease and schizophrenia patients, the researchers said in a news release from Columbia University Medical Center.
"The difference was so great that at first we almost didn't believe it," study first author Dr. Bradley Peterson, director of child and adolescent psychiatry and director of MRI research at Columbia and the New York State Psychiatric Institute, said in the news release. "But we checked and re-checked all of our data, and we looked for all possible alternative explanations, and still the difference was there."
A thinner cortex might increase depression risk by disrupting the ability to pay attention to, and interpret, social and emotional cues from other people, he said. Tests conduced on study participants showed that the thinner the right cortex, the worse a person did on attention and memory tests.
"Our findings suggest rather strongly that if you have thinning in the right hemisphere of the brain, you may be predisposed to depression and may also have some cognitive and inattention issues," Peterson said. "The more thinning you have, the greater the cognitive problems. If you have additional thinning in the same region of the left hemisphere, that seems to tip you over from having a vulnerability to developing symptoms of an overt illness."
He said that the findings, which appear online in this week's online issue of the Proceedings of the National Academy of Sciences, could help lead to new ways of treating or preventing depression.
Columbia University Medical Center, news release, March 23, 2009