Differences in demographic, clinical and substance use characteristics are important considerations for the treatment and recovery of persons with SMIs [9–10, 12, 14, 16, 33–35]. For example, a first-episode psychosis (FEP) study showed a greater proportion of males used substances compared to females, and that cannabis use was associated with greater degrees of positive symptomatology [9]. A similar study of FEP patients associated persistent drug/alcohol use with poorer remission rates from substances of abuse [10]. A study of adults with schizophrenia-spectrum disorders showed multiple substances were used in the sample, a greater proportion of males were diagnosed with SUDs, and alcohol use was associated with greater degrees of positive symptomatology [8]. A 10-year investigation of patients with schizophrenia-spectrum and bipolar disorders revealed alcohol use was associated with poorer rates of achieving a 6-month remission status over the follow-up period [14]. However, a three-year study revealed patients generally achieved remission from substances of abuse, with schizophrenia-spectrum disorder patients faring less well in terms of hospital readmission compared to patients with bipolar disorders [12, 16]. An investigation of adults with bipolar disorders
