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Burden of schizophrenia increasing globally

Findings from the 2016 global burden of disease study indicated that population growth and aging has led to an increasing disease burden attributable to schizophrenia globally, especially in middle-income countries.

“Developing health services for schizophrenia will require robust and informative epidemiological estimates, including estimates of the number of people living with schizophrenia in a given population and how these have changed over time — estimates that are currently unavailable for schizophrenia,” Fiona J. Charlson, MIPH, PhD, of the University of Queensland School of Public Health in Australia, and the Institute for Health Metrics and Evaluation at University of Washington, and colleagues wrote. “Recent innovations in statistical modeling, as part of the global burden of disease studies, have allowed for the derivation of detailed and comparable epidemiological estimates for schizophrenia by age, sex, geography, and year.”

Charlson and colleagues reported the global disease burden study 2016 estimates of schizophrenia prevalence and burden of disease. In this systematic review, the researchers identified studies reporting the prevalence, incidence, remission and/or excess mortality relating to schizophrenia, then entered estimates into the Bayesian meta-regression tool used in the 2016 global disease burden study to obtain prevalence for 20 age groups, seven super-regions, 21 regions and 195 countries/territories. They obtained burden of disease estimates for schizophrenia by multiplying the prevalence specifically for age, sex, year and location.

In total, 129 individual data sources were included in the systematic review. The results showed that the prevalent cases rose from 13.1 (95% uncertainty interval [UI], 11.6–14.8) million in 1990 to 20.9 (95% UI, 18.5–23.4) million cases in 2016 worldwide. According to the global disease burden study, schizophrenia contributes 13.4 (95% UI, 9.9–16.7) million years of life lived with disability to the worldwide burden of disease.

Analysis demonstrated that the estimated global age-standardized point prevalence of schizophrenia in 2016 was 0.28% (95% UI, 0.24–0.31), with no differences between sexes. Furthermore, there were no large differences between age-standardized point prevalence rates across countries or regions globally.

Globally, an estimated 21 million people are living with schizophrenia and this number will continue to rise with population ageing and growth, according to the researchers. The findings showed that most people live in low- and middle-income countries.

“Health systems in low- and middle-income countries need to prepare for this increase, but existing evidence-based interventions have been poorly implemented, with only 31% of people with schizophrenia accessing treatment in low- and middle-income countries, where the overall mental disorders treatment gap is as high as 89%,” Charlson and colleagues wrote in Schizophrenia Bulletin.

Differences in disability adjusted life years per income status showed that the burden of schizophrenia experienced in lower- and upper-middle income countries was roughly four times that experienced by high-income countries, largely due to the growing populations of these lower income countries.

“This calls for an urgent scaling up of services to respond to serious mental disorders such as schizophrenia,” the researchers wrote. “Health systems in most countries are unprepared for this escalating burden and without action to scale-up services, a lack of effective treatment for this debilitating mental disorder will critically impact individuals and their families.” – by Savannah Demko

Disclosures: Charlson reports support from an Australian National Health and Medical Research Council Early Career Fellowship. Please see the full study for all other authors’ relevant financial disclosures.