Association of polymorphism (Val66Met) of brain-derived neurotrophic factor with suicide attempts in depressed patients

Introduction: Recent post-mortem studies of suicide victims have implicated brain-derived neurotrophic factor (BDNF) in suicide. Therefore, it was decided to examine the possible role of a gene in the regulation of BDNF activity in relation to suicidal behaviour among depressed patients. Method: A series of 170 depressed patients were evaluated for their history of suicide attempts and genotyped for the BDNF Val66Met polymorphism (SNP ID: rs6265). Depressed patients who had (n = 97) or had not (n = 73) attempted suicide were compared. Results: Depressed patients who carried the BDNF Val66Met polymorphism variant (GA + AA) appeared to show a significantly increased risk of suicidal behaviour. The risk of a suicide attempt was also significantly higher among those reporting higher levels of childhood emotional, physical and sexual abuse. Secondary analyses suggested that depression severity was a significant risk factor only in the wild-type BDNF genotype, and that the risk of suicide attempts was more predictable within the wild-type group. Conclusion: These preliminary data suggest that BDNF may play a role in the suicidal behaviour of depressed patients.