Executive function in methamphetamine users with and without psychosis.

Methamphetamine abuse is associated with cognitive deficits across a wide range of domains. It is unclear, however, whether methamphetamine-dependent individuals with co-occurring psychosis are more impaired than those without psychosis on tests assessing executive function. We therefore aimed to compare the executive function performance of three groups: methamphetamine-dependent individuals with methamphetamine-induced psychosis (MA+; n = 20), methamphetamine-dependent individuals without psychosis (MA-; n = 19), and healthy controls (HC; n = 20). All participants were administered a neuropsychological test battery that assessed executive functioning across six sub domains (problem solving, working memory, verbal generativity, inhibition, set switching, and decision making). Analyses of covariance (controlling for between-group differences in IQ) detected significant between-group differences on tests assessing verbal generativity and inhibition, with MA+ participants performing significantly more poorly than HC. The finding that methamphetamine-induced psychosis is associated with performance impairments in particular subdomains of executive function may have implications for treatment adherence and relapse prevention.