I wanted to draw attention to a new paper in JAMA recently because it reveals a lot about how conditional most of the statements we make in behavioral genetics are. Every time you hear a news article that says, “Gene for depression found,” I want you to think about this case.
Risch et al. performed a meta-analysis on 14 studies that were looking at Serotonin Transporter (5-HTTLPR) genotype and number of stressful life events. These two factors were related to the subsequent risk for developing clinical depression. Their analysis found — contrary to a very well known study, Caspi et al. — that there was no association between genotype for this gene and depression risk and no significant interaction between genotype and number of stressful life events.
I think this case is a good example of why we should be skeptical of behavioral genetics studies reported in the news until they have been replicated repeatedly.