Research shows a link between a particular allele for serotonin found at a higher frequency in those at risk of depression because of family history and others.

‘Familial risk for depression and brainplasticity might play a role in increasing the risk of developing depression.’

Prior work by Bradley S. Peterson, MD, director of the Institute for the Developing Mind (IDM) at Children's Hospital Los Angeles, and colleagues showed that individuals at familial risk for depression -- whether or not they have exhibited signs of depression in the past -- have a pattern of thinning in certain cortical regions of the brain. Additional brain loss occurs in other areas of the brain in those who do manifest depressive symptoms. 




Several genes have been associated with depression, especially those genes that alter serotonin signaling. Serotonin is a chemical messenger in the brain that acts as a mood stabilizer. A genetic variation, or allele, found in the promoter region of the serotonin transporter was found to affect this brain loss.
The study found that among those at low risk for depression, the "S" (short) allele is associated with a thinner cortex than those with the "L" (long) allele. However, in the individuals at high risk for depression because of their family history, the correlation is actually reversed and more cortical thinning is found in those with the "L" allele.
In addition, those with the "S" allele were at higher risk of developing depression than those with the "L" allele when exposed to the same type and amount of stressors.
"These findings suggest that brain plasticity also plays a role in depression," said first author Ravi Bansal, PhD, researcher at the IDM at Children's Hospital Los Angeles and professor of pediatrics at Keck School of Medicine of the University of Southern California. "It could be that those with the "L" allele or genetic variation can better adapt to their environment. Those with the "S" allele appear to have lower brain plasticity and perhaps have fewer compensatory factors in the brain that allow them to adapt to adverse conditions."
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Source-Eurekalert