Study Calculates Disability Caused by Schizophrenia

Abstract

Back to table of contents Previous article Next article Clinical & ResearchFull AccessStudy Calculates Disability Caused by SchizophreniaNick ZagorskiNick ZagorskiSearch for more papers by this authorPublished Online:23 Aug 2021https://doi.org/10.1176/appi.pn.2021.9.31AbstractAn analysis using Danish registry data finds that though major depression was the most prevalent mental disorder in Denmark, schizophrenia was the leading cause of disability due to mental illness for both men and women, accounting for 273 years living with disability per 100,000 person-years.Making use of the abundant medical data available in Danish national health registries, researchers have developed new estimates on the amount of disability associated with different mental health and substance use disorders.When factoring in both the duration of illness and severity of disability, John McGrath, M.D., Ph.D., the Niels Bohr Professor at the National Centre for Register-based Research at Aarhus University in Denmark, and colleagues found schizophrenia to be the most burdensome mental illness at both an individual and population level. Personality disorders were second most disabling in both sexes, followed by anxiety disorder in women and alcohol use disorder in men. These findings were published in The Lancet Psychiatry.While previous studies have examined how mental and substance use disorders contribute to years lived with disability (YLD), these studies have largely relied on average incidence, remission, and prevalence rates in the population. McGrath’s team, together with researchers from Queensland Centre for Mental Health Research in Brisbane, Australia, instead relied on individual data from medical registries to calculate YLD. Such data included when people were diagnosed, how severe their symptoms were, and if/when they achieved remission.Using data from the Danish Psychiatric Central Research Register, McGrath and colleagues calculated the YLD for 18 mental health and substance use disorders. The YLD is calculated by multiplying the duration of an illness with a predefined disability index ranging from 0 to 1. (For example, the disability index of major depression is 0.15 for mild symptoms, 0.40 for moderate symptoms, and 0.66 for severe symptoms.)Though major depression was the most prevalent disorder in Denmark, schizophrenia was the leading cause of disability due to mental illness for both men and women, accounting for 273 YLDs per 100,000 person-years. Personality disorders were the secondmost disabling, followed by anxiety disorders.In contrast, most substance use disorders (with the exception of alcohol) contributed relatively little YLDs in the population. McGrath said these data should not imply that substance use is a minor societal concern in Denmark. “Our study focused on disability; if we had also looked at mortality, then substance use disorders would be near the top,” McGrath said. “Whether it’s overdoses, traffic accidents, or liver disease, alcohol and drugs are huge when it comes to years of life lost.”To gain more insight into disability at an individual level, McGrath and colleagues devised a metric called the Health Loss Proportion (HeLP) to quantify the disability associated with all mental comorbidities experienced by a person. On the individual level, schizophrenia was still the most disabling, as the researchers calculated the average person with schizophrenia loses 73% of his or her healthy life per year. Opioid use disorder (OUD) was second, resulting in a 67% loss of healthy life each year. (OUD is rare in Denmark, which is why it was not one of the top disorders for YLD at the population level.)For patients with schizophrenia and a comorbid disorder, the schizophrenia itself was the primary contributor of the disability, as was the case for patients with comorbid conduct disorder and autism spectrum disorder. But among other disorders, notably various substance use disorders, disability was heavily influenced by comorbid conditions the patients had.“These HeLP data reveal the subtle nuances in how different mental health disorders affect a person’s quality of life,” McGrath told Psychiatric News. “These HeLP metrics provide compelling evidence that we need mental health services that are better equipped as one-stop shots for a range of problems.”This study was supported by the Danish National Research Foundation. ■“Register-based Metrics of Years Lived With Disability Associated With Mental and Substance Use Disorders: A Register-Based Cohort Study in Denmark” is posted here. ISSUES NewArchived