Conventional scientific wisdom, occasionally repeated in the posts of this list, is that the smart money in psychology is going to be on gene- environment interaction as the cause of variability in human behaviour. Some speak as though this claim has already been amply demonstrated.
The reality, however, is that while this is a fine idea in principle, the evidence currently demonstrating such interaction is sparse and inconsistent. As a notorious scoffer of conventional wisdom, I keep an eye out for studies demonstrating that what everyone thinks is true isn't necessarily so. Sometimes I'm rewarded. Consider the claim that there is a gene for depression, and the unhappy (literally) possessors of this gene who experience stressful life events become depressed. That is, depression requires both (a) a particular genotype and (b) unpleasant experiences, a gene-environment interaction. The gene in question is believed to control serotonin transport back into the neuron after release into the synapse. And, of course, this belief supports the use of selective serotonin reuptake inhibitor drugs (SSRI's), such as famous Prozac, to treat depression. Risch et al (2009) have just reported a meta-analysis of 14 studies of this issue. They report that depression was found to be associated with the number of stressful life events, which surprises me not at all. It indicates merely that when bad things happen to you, you feel bad. More interesting is what they did not find. They found no evidence that the serotonin transporter gene was associated with depression, and no evidence of an interaction with stressful life events. In their words: "This meta-analysis yielded no evidence that the serotonin transporter genotype alone or in interaction with stressful life events is assocated with an elevated risk of depression in men alone, women alone, or in both sexes combined." Stephen Risch, N. et al (2009). Interaction between the serotonin transporter gene (5-HTTLPR), stressful life events, and risk of depression. JAMA, 301: 2462-2471. ----------------------------------------------------------------- Stephen L. Black, Ph.D. Professor of Psychology, Emeritus Bishop's University e-mail: [email protected] 2600 College St. Sherbrooke QC J1M 1Z7 Canada Subscribe to discussion list (TIPS) for the teaching of psychology at http://flightline.highline.edu/sfrantz/tips/ ----------------------------------------------------------------------- --- To make changes to your subscription contact: Bill Southerly ([email protected])
