Specific genetic variations have recently been shown to correlate with the risk for depression. As mentioned before, serotonin is an important chemical messenger in the brain associated with mood (see June 27, 2010 blog). The length of the gene for the serotonin transporter appears to be associated with depression risk. This gene essentially comes in two forms, a long-form, and a short form. Patients with the short form produce fewer serotonin transporters, and it turns out that these individuals are more susceptible to depression when exposed to traumatic life experiences.
Although this finding is not without controversy, it has been held up as an example of the interaction between genetics and one’s environment (instead of nature vs. nurture, what seems more likely is a combination of nature and nurture). The length of this transporter gene may, therefore, be one of many genetic factors that contribute to resiliency — the way that people are able to bounce back from adversity. This finding also further validates the approach of enhancing serotonin activity to treat depression (such as with the SSRIs).
Regards, Dr. Ranen (Psychiatrist Baltimore, Baltimore County, Owings Mills) DrNealRanenBaltimorePsychiatrist.com