Disparities in the incidence and prevalence of psychotic disorders among people with and without disabilities in south Korea: A national database study.

Background: Numerous epidemiological studies on psychotic disorders have been conducted, however, most were from an etiological perspective, used small sample sizes, or focused on a limited number of disabilities. Few studies have investigated all types of disabilities over a long observation period, and none have included the entire adult population of a country. To explore potential differences in the incidence and prevalence of psychotic disorders between patients with and without disabilities, we conducted a serial cross-sectional study.

Methods: This study was conducted using a data set linking the Korean National Health Insurance Service database, and disability registration data. Age-standardized incidence or prevalence rates were calculated for each year during 2008-2017 according to the presence, severity, and type of the disability. Factors associated with psychotic disorders were examined by multivariate logistic regression using the most recent data.

Results: The age-standardized incidence and prevalence of psychotic disorders were higher among people with disabilities than among those without disabilities across all age groups, with particularly high rates observed among people with severe disabilities and those with intellectual disabilities. The gap in the prevalence of psychotic disorders between people with and without disabilities has widened over time. In regression analyses, adjusting for sociodemographic characteristics and mental health substantially reduced the odds ratios.

Conclusions: The incidence and prevalence of psychotic disorders were higher in people with disabilities, especially those with severe disabilities, and intellectual disabilities. Policy efforts are needed to narrow the gap people with and without disabilities.