The prevalence of physical multimorbidity among people with non-affective psychotic disorders 10 years after first diagnosis: a matched retrospective cohort study

Aims: The higher prevalence of chronic physical health conditions among people with psychotic disorders may result in a reduced life expectancy as compared to the general population. More research is needed on the risk of multiple co-occurring chronic health conditions, known as multimorbidity, for people with psychotic disorders. Methods: We conducted a matched retrospective cohort study to quantify the prevalence of multimorbidity and associated factors among people with psychotic disorders over the 10-year period following first diagnosis, relative to those without psychosis. Data from an early psychosis intervention program in London, Canada were linked to population-based health administrative data to identify patients with first-episode psychosis (n = 439), and a comparison group from the general population (n = 1759) matched on age, sex, and postal code. We followed the cohort for 10 years to ascertain the prevalence of multimorbidity. We compared people with and without psychosis using modified Poisson regression models, and explored risk factors for multimorbidity among those with psychotic disorders. Results: People with psychotic disorders may have a 26% higher prevalence of multimorbidity 10 years following first diagnosis, although our findings include the possibility of a null effect (PR = 1.26, 95% CI 0.96–1.66). People with psychosis living in areas with the highest levels of material deprivation had a threefold higher prevalence of multimorbidity as compared to those in the lowest areas of material deprivation (PR = 3.09, 95% CI 1.21–7.90). Conclusion: Multimorbidity is prevalent among those with psychosis, and assessment for chronic health conditions should be integrated into clinical care for younger populations with psychotic illness