childhood symptoms of inattentionhyperactivity predict cannabis use in first episode psychosis background a history of childhood symptoms of inattentionhyperactivity is often reported in first episode psychosis fep as is cannabis use in the general population childhood adhd predicts future cannabis use but the relationship has not been tested in fepmethod parents of patients with a first episode of psychosis n75 retrospectively assessed their affected child for symptoms of earlylife disorders namely attention deficit hyperactivity disorder adhd conduct disorder cd and oppositional defiant disorder odd using the child behaviour checklist cbcl assessments were made prospectively of cannabis use over two years following a fep and of scid diagnosis of cannabisuse disorderresults childhood hyperactivityinattention symptoms predicted inability to maintain abstinence from cannabis following treatment wald84 p004 and lifetime cannabisuse diagnosis wald53 p022 in a logistic regression controlling for relevant covariates including symptoms of cd and odd from ages 12 to 18 when the symptom of inattention was considered in place of the hyperactivityinattention syndrome it predicted cannabisuse diagnosis wald64 p011 and persistent abstinence from cannabis wald53 p021 symptoms of cd and odd did not predict cannabis use when hyperactivityinattention symptoms were controlled forconclusions symptoms of childhood inattentionhyperactivity predict subsequent cannabis use in fep