Genes, environment, and depression

This press release from Duke has some surprising news about a common variant of a gene that affects the availability of serotonin in the brain. Women who had experienced significant stress at some time in their lives and carried a shorter form of the gene showed more signs of depression than women who had the longer variant or were not stressed, but for men it was the long variant that was associated with more symptoms of depression, and the short variant was linked to fewer symptoms. The two sources of stress the study looked at were growing up poor, or caring for someone with Alzheimer’s disease or another form of advanced dementia. (I.e., they didn’t necessarily have to be current stressors.) I’m assuming the gene in question is SLC6A4, which encodes for the serotonin transporter (SERT) protein. (If you’ve heard earlier news about a gene related to serotonin transport being linked with depression, that’s the one.) This story gives an interesting twist to the fact that genes by themselves do not tell the whole story of who we are and how we work; environmental factors are also part of the story.