Abstract
Cognitive impairments are commonly observed in individuals who use stimulants, yet few studies have tracked these individuals longitudinally. This prospective, 12-month longitudinal study investigated changes in cognitive functioning among active stimulant users and explored the associated factors. Adults with recent stimulant use were recruited from substance misuse treatment clinics and the community. Their demographics, history of drug use, and stimulant use disorder severity were assessed with structured clinical interviews. Global cognitive function and frontal executive function were measured every three months using the Montreal Cognitive Assessment (MoCA) and the Frontal Assessment Battery (FAB) over one year. Linear mixed-effects models evaluated temporal trajectories and associated factors related to the Changes in cognitive functions. Among 76 analysed participants, their frequency of stimulant uses were active and stable over 12 months. The MoCA scores averaged below the clinical cut-off at baseline, although no further persistent decline was observed. In contrast, FAB scores presented no systematic temporal changes. Being female and being of older ages were found to be associated with lower MoCA and FAB. None of severity, education, recent stimulant use, and lifetime duration of use, were found to be associated with cognition. While stimulant users exhibited some modest cognitive declines at baseline, no further substantial cognitive deterioration was observed over the one-year study period. Cognitive outcomes were more strongly associated with demographic factors than SUD severity or stimulant use patterns. These findings highlight the need for more sensitive tools to detect subtle cognitive changes associated with stimulant uses.