A genetic risk factor for major depression and suicidal ideation is mitigated by physical activity.

We evaluated associations of five candidate polymorphisms (Bcl1 [rs41423247], -2C/G [rs2070951], COMT [rs737865], Val66Met [rs6265], and 5HTTLPR [biallelic and triallelic [5HTTLPR/rs25531]) with probable MDD and suicidal ideation (SI), the effects of physical activity on these endpoints, and whether physical activity attenuates genetic risk in military members (N=736). C carriers who were also less physically active were 3.3 times as likely to meet criteria for probable MDD and 9.6 times as likely to endorse SI as compared to physically active GG carriers. An adequate dose of physical activity diminishes risk of MDD and SI imposed by a genetic predisposition.