Cannabis use in children and adolescents with first episode psychosis: influence on psychopathology and short-term outcome (CAFEPS study).

ABSTRACT

OBJECTIVE: To know the prevalence of substance use and its relationship with psychopathology at onset and after six months in children and adolescents with first episode psychosis (FEP). METHOD: 110 FEP patients, aged 9-17, were assessed for substance use, and with the Positive and Negative Syndrome Scale (PANSS) and other psychopathological and general functioning scales at baseline and after a six-month follow-up. RESULTS: Patients' substance use at baseline was tobacco (30.9%), cannabis (29.1%), alcohol (21.8%), cocaine (8.2%), amphetamines (2.7%), LSD (1.8%) and opiates (0.90%). Six months later, there was a decrease in patients' use of cannabis (p=0.004) and other drugs, except tobacco. Patients were divided, according to their baseline cannabis use, into 32 cannabis users (CU) and 78 non-cannabis users (NCU). CU were older (p=0.002) and had higher PANSS positive scores (p=0.002) and lower PANSS negative (p<0.001), PANSS general (p=0.002) and PANSS total (p=0.007) scores than NCU. At six months, CU had significantly lower PANSS positive (p=0.010), negative (p=0.0001), general (p=0.002) and total (p=0.002) scores than NCU. When we divided CU at six months into previous CU (n=16) and current CU (n=15), previous CU had the best outcome, NCU the worst and current CU had an intermediate profile. CONCLUSIONS: Cannabis use may be related to higher positive symptom scores for FEP patients, with greater improvement after six months for those who cease using cannabis.