ImportanceAdolescent media use is thought to influence mental health, but whether it is associated with psychotic experiences (PEs) is unclear.ObjectiveTo examine longitudinal trajectories of adolescent media use and their associations with PEs at 23 years of age.Design, Setting, and ParticipantsThis cohort study included participants from the Québec Longitudinal Study of Child Development (1998-2021): children who were born in Québec, Canada, and followed up annually or biennially from ages 5 months through 23 years. Data were analyzed between January 2023 and January 2024.ExposuresParticipants reported their weekly amount of television viewing, video gaming, computer use, and reading at ages 12, 13, 15, and 17 years.Main Outcome and MeasuresLifetime occurrence of PEs was measured at 23 years of age. Covariables included sociodemographic, genetic, family, and childhood characteristics between ages 5 months and 12 years.ResultsA total of 1226 participants were included in the analyses (713 [58.2%] female, 513 [41.8%] male). For each media type, latent class mixed modeling identified 3 group-based trajectories, with subgroups following trajectories of higher use: television viewing, 128 (10.4%); video gaming, 145 (11.8%); computer use, 353 (28.8%); and reading, 140 (11.4%). Relative to lower video gaming, higher video gaming was preceded by higher levels of mental health and interpersonal problems at age 12 years. Adjusting for these risk factors mitigated the association between higher video gaming and PEs at age 23 years. The curved trajectory of computer use (189 [15.4%] participants), characterized by increasing levels of use until age 15 years followed by a decrease, was associated with higher PEs (estimated difference, +5.3%; 95% CI, +1.5% to +9.3%) relative to lower use (684 [55.8%] participants). This association remained statistically significant after covariable adjustment.Conclusions and RelevanceThis study found that longitudinal trajectories of media use during adolescence were modestly associated with PEs at age 23 years, likely reflecting the influence of shared risk factors. Understanding the environmental determinants and psychosocial functions of media use during adolescence may help better integrate digital technologies in the prevention and management of PEs.