The association between brain-derived neurotrophic factor polymorphism (BDNF Val66Met) and suicide

BackgroundBrain-derived neurotrophic factor (BDNF) mediates neural plasticity, mood, different behaviours, and stress response. A functional BDNF polymorphism (BDNF Val66Met) was reported to influence the effects of stressful life events or childhood adversity on depression and suicidal behaviour in various psychopathologies. The study evaluated the association between BDNF Val66Met variants and suicide, committed with violent or non-violent methods, in victims with or without stressful childhood experience.MethodsBDNF Val66Met polymorphism was genotyped on 560 DNA samples from 359 suicide victims and 201 control subjects collected on autopsy from unrelated Caucasian subjects and subdivided according to gender, method of suicide, and influence of childhood adversity.ResultsA similar frequency of BDNF Val66Met variants was found between all included suicide victims and the control groups, and also between the male groups. The frequency of the combined Met/Met and Met/Val genotypes and the homozygous Val/Val genotype was significantly different between the female suicide victims and female controls, between the female suicide victims who used violent suicide methods and female controls, and between all included suicide victims with or without stressful life events. The combined Met/Met and Met/Val genotypes contributed to this significance.LimitationA small group of suicide victims with available data on childhood adversity was studied.ConclusionsThe combined Met/Met and Met/Val genotypes of the BDNF Val66Met variant could be the risk factor for violent suicide in female subjects and for suicide in victims exposed to childhood trauma. These results confirm a major role of BDNF in increased vulnerability to suicide.