Brain-derived neurotrophic factor (Val66Met) genetic polymorphism is associated with substance abuse in males

Data from animal studies and from genetic scans in humans suggest that brain-derived neurotrophic factor (BDNF), a member of the neurotrophic factor family, may be involved in the mechanisms underlying substance abuse. The present study tested the hypothesis that the BDNF-gene Val66Met polymorphism is associated with substance abuse. We studied this polymorphism in 103 methamphetamine- and 200 heroin-dependent cases and 122 normal controls. We also considered the association of this polymorphism with age of onset of substance abuse in the hero in-dependent cases. Significant differences in BDNF Val66Met genotype distribution were found between subjects dependent on methamphetamine (P = 0.046) or heroin (P = 0.045) and controls, suggesting that the lower 66Met carrier frequency is associated with substance abuse. Furthermore, in the heroin-dependent group, the Val/Val homozygotes had a later onset of substance abuse compared with the Met allele carriers. The results suggest that the BDNF Val66Met polymorphism or a nearby locus may be involved in the pathogenesis of substance abuse. Our findings support previous genetic scan results showing that BDNF may contribute to substance abuse vulnerability. (c) 2005 Elsevier B.V. All rights reserved.