The Ramazzini Institute
for Occupational and Environmental Health Research   

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Human Ecology
Gene + Environment = Depression?
     A genetic vulnerability to stress makes us more than twice as likely to develop depression after crises of life, such as job loss or death in their family, as those with a version of the same gene that appears to provide protection, Terrie Moffitt, of King's College, London, and his colleagues have discovered.
     In a study published July 18 in Science, possibly for the first time, a mental disorder has been linked to the interaction of genes and the environment. Prior studies of genetic factors of depression and other mental illnesses assumed direct paths from genes to mental illnesses.
     The study helps explain why only some people who go through emotional crises develop depression, signaled by prolonged sadness, work impairment, disrupted personal relationships, despair and suicidal behavior. Others fare better because of a genetic difference.
     The study tracked 847 people for five years and showed that 43 percent of those with depression had a short form of the serotonin transporter gene. Of those with the long form, 17 percent developed depression after experiencing emotional trauma. The environmental factors were more significant than genetic factors. Cultural and social differences affect rates of mental illness. This study was done among Caucasian New Zealanders. Genetic variations of the gene have been found in different ethnic groups,