The brain-derived neurotrophic factor gene in suicidal behaviour: a meta-analysis

Suicide is a prominent public health problem. Its aetiology is complex, and the brain-derived neurotrophic factor (BDNF) has been implicated. We performed the first meta-analysis of the functional BDNF marker Val(66)Met (rs6265, 196G> A) in suicidal behaviour using data from 11 previously published samples plus our present sample (total n = 3352 subjects, 1202 with history of suicidal behaviour. The meta-analysis including all 12 studies showed a trend for the Met-carrying genotypes and Met allele conferring risk for suicide (random-effects model p = 0.096; ORMet-carrier = 1.13, 95% CI 0.98-1.30, and random-effects model p = 0.032; ORMet = 1.16, 95% CI 1.01-1.32, respectively). Furthermore, we found the Met allele and the Met allele-carrying genotypes to be associated with history of suicide attempt (eight studies; allelic meta-analysis - random-effects model: p = 0.013; fixed-effects model: p = 0.006; genotypic meta-analysis - random-effects model: p = 0.017; fixed-effects model: p = 0.008). Taken together, the results from our study suggest that BDNF Val(66)Met is involved in suicidality. Further studies are required to elucidate its role in suicidal behaviour.