Childhood symptoms of inattention–hyperactivity predict cannabis use in first episode psychosis

Background A history of childhood symptoms of inattention–hyperactivity 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 FEP. Method Parents of patients with a first episode of psychosis (n = 75) retrospectively assessed their affected child for symptoms of early-life 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 cannabis-use disorder. Results Childhood hyperactivity–inattention symptoms predicted inability to maintain abstinence from cannabis following treatment (Wald = 8.4, p = .004) and lifetime cannabis-use diagnosis (Wald = 5.3, p = .022) 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 hyperactivity–inattention syndrome it predicted cannabis-use diagnosis (Wald = 6.4, p = .011) and persistent abstinence from cannabis (Wald = 5.3, p = .021). Symptoms of CD and ODD did not predict cannabis use when hyperactivity–inattention symptoms were controlled for. Conclusions Symptoms of childhood inattention–hyperactivity predict subsequent cannabis use in FEP.