In this study, we aimed to establish the acute effects of administration of cannabis and cocaine on valence-dependent reversal learning as a function of DRD2 Taq1A (rs1800497) and COMT Val108/158Met (rs4680) genotype.
Working memory following cannabis acutely was worse in females, with some suggestion of an impact of COMT polymorphism on working memory when drug-free.
Epidemiological and retrospective studies suggest a cannabis x catechol-O-methyltransferase (COMT) Val(158)Met interaction effect on development of psychosis.
A functional polymorphism in the catechol-O-methyltransferase (COMT) gene (Val(158)Met) appears to influence the immediate cognitive and psychotic effects of cannabis, or ∆(9)-tetrahydrocannabinol (THC), its primary psychoactive ingredient.
Adolescents with the Met/Met genotype and high rates of MB-COMT promoter methylation were less likely to be high-frequent cannabis users than adolescents with the Val/Val or Val/Met genotype.
The results showed that the COMT polymorphism influenced the volume of the bilateral ventral caudate nucleus in both groups, but in an opposite direction: more copies of val allele led to lesser volume in chronic cannabis users and more volume in controls.
Adolescents with the Met/Met genotype and high rates of MB-COMT promoter methylation were less likely to be high-frequent cannabis users than adolescents with the Val/Val or Val/Met genotype.
Cannabis users carrying the COMT val/val genotype exhibited lower accuracy of sustained attention, associated with a more strict response bias, than val/val non-users.
A putative interaction between cannabis and variation at rs4680 within the catechol-methyl-transferase (COMT) gene on psychosis has been reported, but not adequately replicated.
Cannabis has been reported as a likely risk factor for the development of psychosis, and a gene × environment interaction with the catechol-O-methyltransferase (COMT) gene has been proposed.
The findings confirm that in people with psychometric evidence of psychosis liability, COMTVal(158)Met genotype moderates the association between cannabis and psychotic phenomena in the flow of daily life.
Observational studies have suggested that psychometric psychosis liability and a functional polymorphism in the catechol-O-methyltransferase (COMTVal(158)Met) gene moderate the psychosis-inducing effect of cannabis.