Drug use disorders are one of the most common mental health problems and are often associated with an adverse impact neuropsychological functioning. Drugs of abuse have common and unique effects on neurocognitive functioning. Here, we review the literature on substance use effects on neurocognitive functioning by drug class (i.e., benzodiazepines, cannabis, cocaine, MDMA, methamphetamines, and opiates). Heterogeneity among participant samples within and across drug classes provides a complex picture of how drug use impacts neuropsychological functioning. Overall, more severe patterns of drug use (e.g., substance use disorder) are associated with poorer neuropsychological functioning. It is unclear whether the deficits in neuropsychological functioning observed among drug users predate drug use or are consequence of drug use. Prospective longitudinal studies will help in our understanding of how drug use and neuropsychological deficits are associated.
