Although substance misuse is consistently reported in First Episode Psychosis (FEP) patients, reliable clinical correlates of substance use in patients with a FEP have yet to be identified. Accumulated evidence indicates that concurrent substance use plays an important role in the development, course and treatment of FEP patients as it is associated with more pronounced positive symptoms, shorter Duration of Untreated Psychosis (DUP), higher number of hospitalizations, reduced illness insight, increased medication and treatment non adherence and service disengagement, higher relapse rates, poorer outcome and higher costs for mental health services . A reduction in substance use after diagnosis is associated with a reduction in subsequent admissions and psychotic symptoms ]. However, around three quarters of patients with a lifetime diagnosis of substance misuse continue to misuse after the initiation of treatment. Alcohol and cannabis are the substances most frequently used in FEP patients .