No association between serotonin transporter gene and depression
About a month ago, a meta-analysis examining all studies of association between serotonin transporter gene (5-HTTLPR), stressful life events and depression was published in JAMA, June 17, 2009 issue by Neil Risch and Richard Herrell and colleagues. This is one of the first attempts at using a meta-analysis technique to test an interaction between a gene polymorphism and environmental factor (stressful life events) on risk of disease (depression). Using the original data from 14 studies combined, the results did not find a significant effect with either the 5-HTTLPR polymorphism or with the interaction between this gene and stressful life events. As with many genetic association studies, the 5-HTTLPR gene was not consistently association with depression and the interaction with stressful life events did not hold up across all the studies. While this may feel like a setback for psychiatric genetics, it is also a reminder that as is always the case in epidemiology (but perhaps not as stringent in the geneticist’s mind), replication of results is one of the criteria before we can assume caustion between two factors. While I have been hesistant to use meta-analyses to prove the existence of an association, this one provides pretty strong evidence of a lack of an association between this gene and depression.
