In summary, the prevalence of substance use in severe psychosis has been underestimated, and spans social and cultural strata. This is the largest study of substance use in individuals with severe psychotic illness to date. The study not only highlights the comorbid pathology of substance use among those with severe psychotic illness, it also suggests that public health efforts to reduce substance use have not been successful in one of our most vulnerable populations, individuals with severe psychotic illness. It is time to use our recent scientific and public health advancements to improve scientific understanding of the comorbidity between substance use and psychotic disorders, and improved treatment of both.
