Recreational cannabis use over time in individuals at clinical high risk for psychosis: Lack of associations with symptom, neurocognitive, functioning, and treatment patterns

•The current longitudinal study examined the impact of continuous cannabis usage over 2-yearson relevant outcomes in individuals at clinical high risk (CHR) for psychosis.•A small, but unique subsample of high-risk participants continuously used recreational cannabis (N = 12).•Relative to those that did not use cannabis (N = 118), continuous use did not worsen attenuated positive and negative symptoms, neurocognitive performance, and social functioning levels.•Clinical symptoms improved over time for all three subgroups, even though the continuous users declined their antidepressant and antipsychotic usage over time, compared to occasional users (N = 40) and non-users. Recreational cannabis use has recently gained considerable interest as an environmental risk factor that triggers the onset of psychosis. To date, however, the evidence that cannabis is associated with negative outcomes in individuals at clinical high risk (CHR) for psychosis is inconsistent. The present study tracked cannabis usage over a 2-year period and examined its associations with clinical and neurocognitive outcomes, along with medication rates. CHR youth who continuously used cannabis had higher neurocognition and social functioning over time, and decreased medication usage, relative to non-users. Surprisingly, clinical symptoms improved over time despite the medication decreases.