The question of whether a functional variant in the promoter of the
serotonin transporter gene (5-HTTLPR) influences response to adversity
and/or antidepressants has generated great interest and controversy. A
review of the literature suggests that the issue is complicated by
differences in methodology and sample ethnicity. When these confounders are
accounted for, there probably is a real, if small, effect of 5-HTTLPR on
response to both serotonin reuptake inhibitors and environmental
adversity.