Prospective study of cannabis use in adolescents at clinical high risk for psychosis: impact on conversion to psychosis and functional outcome

    loading  Checking for direct PDF access through Ovid



Clinical and epidemiological studies suggest an association between cannabis use and psychosis but this relationship remains controversial.


Clinical high-risk (CHR) subjects (age 12–22 years) with attenuated positive symptoms of psychosis (CHR+, n = 101) were compared to healthy controls (HC, n = 59) on rates of substance use, including cannabis. CHR+ subjects with and without lifetime cannabis use (and abuse) were compared on prodromal symptoms and social/role functioning at baseline. Participants were followed an average of 2.97 years to determine psychosis conversion status and functional outcome.


At baseline, CHR+ subjects had significantly higher rates of lifetime cannabis use than HC. CHR+ lifetime cannabis users (n = 35) were older (p = 0.015, trend), more likely to be Caucasian (p = 0.002), less socially anhedonic (p < 0.001) and had higher Global Functioning: Social (GF: Social) scores (p < 0.001) than non-users (n = 61). CHR+ cannabis users continued to have higher social functioning than non-users at follow-up (p < 0.001) but showed no differences in role functioning. A small sample of CHR+ cannabis abusers (n = 10) showed similar results in that abusers were older (p = 0.008), less socially anhedonic (p = 0.017, trend) and had higher baseline GF: Social scores (p = 0.006) than non-abusers. Logistic regression analyses revealed that conversion to psychosis in CHR+ subjects (n = 15) was not related to lifetime cannabis use or abuse.


The current data do not indicate that low to moderate lifetime cannabis use is a major contributor to psychosis or poor social and role functioning in clinical high-risk youth with attenuated positive symptoms of psychosis.

Related Topics

    loading  Loading Related Articles