Introduction: Exercise is effective in the alleviation of depressive symptoms and may have physiological effects similar to those of selective serotonin reuptake inhibitors (SSRI). Recent research has identified the difference in treatment effects across genetic polymorphisms of the serotonin transporter polymorphic region (5-HTTLPR), in which the l allele has been associated with a better response to SSRI compared with the s allele. The purpose of the current research was to examine the antidepressant effects of exercise across 5-HTTLPR genotypes.
Methods: Participants, ages 18–23 yr, were randomly assigned to a 5-wk exercise intervention or a no-treatment control group. Participants completed the Beck Depression Inventory before and after the intervention and provided a saliva sample for DNA analysis.
Results: Exercise resulted in a significant reduction in depressive symptoms compared with the control group. In addition, individuals with at least one l allele demonstrated greater reductions in depressive symptoms compared with ss individuals.
Conclusions: The effects of exercise on depressive symptoms appear to be moderated by 5-HTTLPR genotype, suggesting that the mechanisms responsible for the alleviation of depressive symptoms are similar for exercise and SSRI treatment. Furthermore, these findings suggest that 5-HTTLPR genotype should be a factor in determining the proper line of treatment for depression.