Our study raises an important question that has received little attention in the literature: Is the high prevalence of the S allele in East Asian populations accompanied by high rates of depression or depressive symptoms? Because of enormous variation in how depression is measured across studies, and the selection biases inherent in relying on clinical data, this question is difficult to address. Nevertheless, two reviews based on a large number of comparable community-based studies suggest generally lower rates of depression in East Asian populations [41, 42], despite their presumed unfavorable allele distribution for 5-HTTLPR.
