CANNABIS EXPOSURE AS THE KEY PREDICTOR OF VERBAL EPISODIC MEMORY IN ADOLESCENT CANNABIS USERS

Cognitive outcomes associated with adolescent cannabis use remain inconsistent, partly due to heterogeneous exposure measures and limited data from clinically assessed and abstinent users. This study examined cognitive functioning in referred adolescents with chronic cannabis use and tested whether patterns of cannabis exposure are associated with intellectual functioning and verbal episodic memory. In a cross-sectional design, 62 adolescents were included, comprising 31 adolescents with primary chronic cannabis use and 31 psychiatric clinical controls without cannabis use disorder. Recent substance exposure was verified using urine drug screening and a substance anamnesis assessing age of onset, frequency, amount, duration, and cumulative cannabis exposure. Cognitive functioning was assessed using Wechsler Intelligence Tests, and verbal learning and episodic memory were measured with the Verbal Learning and Memory Test. Group comparisons and multiple regression analyses were conducted to examine between-group differences and within-group associations between cannabis exposure indicators and cognitive outcomes. Adolescents with chronic cannabis use demonstrated lower full-scale intelligence quotients compared with clinical controls, with a effect size, whereas differences in verbal learning and delayed recall between groups were small and not statistically significant. Within the cannabis-using group, earlier age of onset and higher cumulative exposure were significantly associated with poorer verbal learning performance and reduced delayed episodic memory recall, explaining a substantial proportion of variance in memory outcomes. These findings indicate dose- and timing-dependent associations between cannabis exposure and verbal episodic memory in clinically referred adolescents and emphasize the importance of detailed exposure assessment when evaluating cognitive risks related to adolescent cannabis use.