The brain-derived neurotrophic factor (BDNF) is a key regulator of synaptic plasticity and has been suggested to be involved in the pathophysiology and pathogenesis of psychotic disorders, with particular emphasis on dysfunctions of the hippocampus.
The results had adequate statistical power to suggest that BDNFVal66Met was not related to susceptibility to AD or the onset of AD, but that presence of one or two Met alleles of BDNFVal66Met polymorphism might present a risk factor for psychosis in AD.
Our results showed that the distribution of the BDNFVal66Met 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.
Finally, we observe that frontal-cortex DNA methylation in the BDNF gene is correlated with genotype at a nearby nonsynonymous SNP that has been previously associated with major psychosis.
In this first phase of the project, the objective was to investigate the distribution of four candidate genetic polymorphisms for functional psychosis (Ser9Gly DRD3, 5HTTLPR, the VNTR 3'-UTR SLC6A3 and Val66MetBDNF) in a case-control sample.
Preliminary evidence suggests that polymorphisms within the catechol-O-methyltransferase and brain-derived neurotrophic factor genes may interact with psychosocial stress in the development of psychosis; however, extensive further investigations are required to confirm this.
A larger sample size, and evaluation of more single-nucleotide polymorphisms are needed to obtain more robust and conclusive findings regarding the relationship between the BDNF gene and psychosis.
Our finding suggests that the investigated BDNF polymorphism plays an important role in the phenotype of psychosis, but not in the performance of tests of prefrontal cognitive functions analyzed in these patients.