The prevalence of various measures of substance use are much higher among individuals with schizophrenia, schizoaffective disorder (both depressed and bipolar subtype), and bipolar disorder with psychotic features (Table 2). For ease of interpretation, we classified individuals with schizophrenia, schizoaffective disorders, and bipolar disorder with psychotic features as “cases with severe psychotic disorder,” and analyzed substance use with respect to case/control status. The prevalence of these measures is uniformly high in individuals with severe psychotic illness relative to the control populations. The odds ratio of cases versus controls for each measure of substance use is given in Table 3. Overall, the smoking measures were more strongly associated with case/control status than alcohol or other drugs, with estimated odds ratios of 4.61 for smoking >100 cigarettes (p < 1.0 E-325), and 5.11 for daily smoking >1 month (p<1.0 E-325). The estimated odds ratios for alcohol use (OR 3.96, p=1.2 E-188), marijuana use (OR 3.47, p=2.6 E-254), and recreational drug use (OR 4.62, p<1.0 E-325) were also highly clinically and statistically significant.
