we separated age groups as <35 years and 35–54 years. Cox regression models were used to examine the association of mortality with the most common substances used (cannabis and alcohol) after adjusting for age (18–35 years and 35–55 years), gender, race and smoking status. Previous results from our group found no effects of antipsychotics treatment including clozapine on mortality in this population (Kelly et al., 2010) Interactions between cannabis and alcohol use, and between age and alcohol or cannabis use were examined. All tests were two-sided with alpha=0.05.
