The BDNF Val66Met polymorphism is an independent risk factor for high lethality in suicide attempts of depressed patients

Abstract

Some authors have reported an association of BDNF Val66Met polymorphism with suicidal behavior and/or clinical aspects of suicidal attempts. We evaluated, here, the impact of BDNF Val66Met polymorphism on the clinical characteristics of suicide attempts. The study was conducted on a cohort of 120 consecutive patients who were admitted to the Emergency Hospital of Porto Alegre, Brazil, due to a suicide attempt. Variables of univariate analyses were included in a logistic regression model to test whether the risk factors had independent effect. In univariate analyses, sex, BDNF genotype, intent and method of suicide attempt were all risk factors for high lethality in suicide attempts. After logistic regression analysis, male sex (O.R.=3.03; 95% C.I=1.34-6.84; 0.008) and the presence of BDNF 66Met allele (O.R.=2.62; 95% C.I=1.04-6.57; 0.04) were significantly and independently associated with the high lethality in suicide attempts. The present study showed that BDNF 66Met allele is an independent predictor of high lethality in suicide attempts of depressed patients. This finding is important because it might allow earlier identification of patients at high risk for suicide, perhaps providing better tools for clinical care of these patients in the future.

Association of Brain-Derived Neurotrophic Factor G196A and Attempted Suicide: A Case-Control Study in Rural China

“…BDNF 196A was shown to be a risk factor for suicide in some studies conducted among psychiatric populations [11,12,13,14,15]. In our study, we found a protective effect of the BDNF 196A-carrying genotypes on attempted suicide in the elderly population.…”

“…However, their results do not agree. Five studies [11,12,13,14,15] found that the 196A allele was a risk factor for suicidal behavior, while a further 2 studies [16,17] suggested that the 196G allele was the primary risk factor for attempted suicide. On the other hand, other studies [9,18,19,20] did not support the association of the BDNF G196A polymorphism and suicidal behavior.…”

The BDNF gene Val66Met polymorphism as a modifier of psychiatric disorder susceptibility: progress and controversy

“…Frequency of the Met/Met genotype has also been associated with attempted suicide among schizophrenia probands. 215 Of concern, the 66Met allele has been linked to lethality among depressed patients who attempt suicide 216 and the utilization of violent suicide methods among female carriers of a 66Met allele. 217 Adding credence for a role of BDNF in SB, a recent meta-analysis reported that the 66Met allele was significantly associated with history of suicide attempt, 218 while another reported that the 66Met allele was associated with attempted but not completed suicide.…”

Recent molecular genetic studies and methodological issues in suicide research

“…One recent report failed to find an association between BDNF polymorphisms and SB, but found associations of SNPs in NTRK2 gene (encoding TrkB) with suicide attempt in 394 depressed patients, replicated in another population (Kohli et al, 2010). Another study showed that the BDNF Val66Met polymorphism might be associated with lethality in suicide attempts (Schenkel et al, 2010). From the previously mentioned findings, the BDNF-dependent pathway may play an important role in the SB pathogenesis.…”