Methamphetamine is a highly addictive psychostimulant that has surged in popularity worldwide in the last decade.
Brain-derived neurotrophic factor (
BDNF), a member of the
neurotrophic factor family, is widely expressed in the adult mammalian brain and plays an important role in the long-term survival, differentiation, and outgrowth of neurons. Previous studies suggested that the
BDNF gene may be involved in the mechanisms underlying
substance dependence. This study investigated the association of the
BDNF gene Val66Met polymorphism with
methamphetamine dependence and with
psychosis in a Malaysian population with different ethnicities. The
BDNF Val66Met polymorphism was genotyped by PCR-RFLP in 186 male
methamphetamine-dependent subjects and in 154 male controls of four different ethnicities, namely, Malay, Chinese, Kadazan-Dusun, and Bajau. Our results showed that the distribution of the
BDNF Val66Met genotype in Chinese subjects with
methamphetamine dependence (OR=2.6, p=0.015) and
methamphetamine psychosis (OR=0.2, p = 0.034) were significant compared with controls. The frequency of the 66Val allele in
methamphetamine-dependent subjects was higher than that in the control group, suggesting that the 66Val carriers are more susceptible to
methamphetamine dependence. However, 66Val allele frequency in other ethnicities was not significantly different from the controls. The results of the study also showed that in the Chinese
methamphetamine-dependent subjects, there was a difference in allele frequency when comparing those who developed
psychosis and those who did not. Our findings suggest that the
BDNF Val66Met polymorphism may contribute to
methamphetamine dependence and
psychosis in the Chinese population but not in other Malaysian ethnicities.