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A Fine-Grained Longitudinal Study of Adolescent Cannabis Use and Its Relation to Cognitive Performance in Young
Clarissa Janousch1,2,3, Urs Grob4, Lukas Eggenberger1,2
1Experimental Pharmacopsychology and Psychological Addiction Research, Department of Adult Psychiatry and Psychotherapy, University Hospital of Psychiatry Zurich, University of Zurich, Zurich, Switzerland.
Abstract:
Cannabis use in adolescence has been linked to lower adult cognitive function, but the specific contributions of age of onset and usage frequency remain unclear. This study analyzed data from the Zurich Project on Social Development from Childhood to Adulthood (z-proso; N = 1522) to examine associations between adolescent cannabis use and cognitive performance at young adulthood. Cannabis use frequency was self-reported at six time points between ages 11 and 24. Sustained attention, spatial working memory, and visuospatial declarative memory were assessed at age 24. Regressions, repeated-measures ANOVAs with Helmert contrasts, and latent class growth analyses were conducted, all adjusted for prior cannabis use and key sociodemographic and behavioral confounders. Cannabis use at ages 13, 17, and 20 was linked to reduced attention and declarative memory at age 24, especially among almost daily/daily users. No associations were found with spatial working memory. Four usage trajectories were identified but did not differ in cognitive outcomes. Findings highlight nuanced associations, with early and frequent use linked to poorer cognitive performance.
Supplementary Information:
The online version contains supplementary material available at https://doi.org/10.1007/s11469-025-01604-0.