Study shows genetic variation in depressed individuals

By Staff Writer

New research from the University of Michigan reveals that individuals with major depressive disorder may produce lower levels of the brain molecule neuropeptide Y (NPY), which has been shown to restore calm after stressful events. As a result, these people are less resilient to the effects of stress.

For the study, which is published in the Archives of General Psychiatry, researchers used three separate approaches to classify subjects as having low, medium or high NPY gene expression. They then used functional magnetic resonance imaging (fMRI) to observe brain activity as participants listened to neutral words, such as "material," negative words, such as "murder," or positive words, such as "hopeful."

Those in the low NPY group showed strong responses in their prefrontal cortex, which is involved with processing emotion to negative words, compared to individuals in the high NPY group.

The researchers suggest that this is because people with low NPY activate this region of their brain more frequently than others, even in the absence of stress. They conclude that these findings may help doctors diagnose and prevent depression and anxiety in at-risk individuals.