New data published in The Lancet suggest that mental and substance use disorders were the leading causes of nonfatal illness worldwide in 2010.
"Mental and substance use disorders are notable contributors to the global burden of disease, directly accounting for 7.4% of disease burden worldwide," Harvey A. Whiteford, MD, of the School of Population Health at the University of Queensland, Australia, and colleagues wrote. "These disorders were responsible for more of the global burden than were HIV/AIDS and tuberculosis, diabetes, or transport injuries."
Harvey A. Whiteford
Whiteford and colleagues examined data from the 2010 Global Burden of Disease Study (GBD), which has been updated with new mental disorder diagnoses since its publication in 1990, including mood and anxiety disorders, schizophrenia, and pediatric diagnoses such as pervasive developmental disorders. The researchers estimated the global burden of disease — including disability and premature mortality — attributable to 20 mental and substance use disorders in 187 countries.
Overall, mental and substance use disorders were the fifth leading cause of premature mortality and disability worldwide, and accounted for 22.9% (95% CI, 18.6-27.2) of all nonfatal illness — more than any other disease.
Depressive disorders were responsible for approximately two-fifths (40.5%; 95% CI, 31.7-49.2) of the total burden of disease attributable to mental and substance use disorders, followed by anxiety disorders (14.6%; 11.2-18.4), illicit drug use disorders (10.9%; 95% CI, 8.9-13.2), alcohol use disorders (9.6%; 95% CI, 7.7-11.8), schizophrenia (7.4%; 95% CI, 5-9.8), bipolar disorder (7%; 95% CI, 4.4-10.3), pervasive developmental disorders (4.2%; 95% CI, 3.2-5.3), childhood behavioral disorders (3.4%; 95% CI, 2.2-4.7) and eating disorders (1.2%; 95% CI, 0.9-1.5).
Females aged at least 10 years faced the greatest burden from mental disorders, whereas men had the greater burden with substance use disorders across all age groups.
The GBD data also suggested significant variations in the burden of mental and substance use disorders between world regions. For example, the proportion of death and disability linked to eating disorders was 40 times higher in Australasia compared with western sub-Saharan Africa, and the burden from alcohol use disorders varied more than 10 times between world regions.
According to the researchers, the burden of mental and substance use disorders increased by 37.6% from 1990 to 2010, driven primarily by growing and aging populations.
In a press release, Whiteford said barriers to mental health care must be addressed to reduce the global prevalence of mental and substance use disorders.
"Despite the personal and economic costs, treatment rates for people with mental and substance use disorders are low, and even in developed countries, treatment is typically provided many years after the disorder begins," he said. "In all countries, stigma about mental and substance use disorders constrain the use of available resources as do inefficiencies in the distribution of funding and interventions. If the burden of mental and substance use disorders is to be reduced, mental health policy and services research will need to identify more effective ways to provide sustainable mental health services, especially in resource constrained environments."
A second study (Degenhardt and colleagues), which was published alongside the Whiteford study, looked at the global and regional prevalence and effect of four major drugs types: amphetamines, cannabis, cocaine and opioids.
The researchers, who also analyzed the 2010 GBD data, said opioid dependence was responsible for the greatest burden of disease among all illicit drugs, accounting for 55% of the 78,000 deaths linked to drug use in 2010.
More than two-thirds of individuals dependent on drugs were male — 64% each for cannabis and amphetamines and 70% each for opioids and cocaine, and the proportion of drug dependence increased in the highest-income countries.
According to the researchers, disability and illness related to the four drug types increased by 52% from 1990 to 2010; population growth (28%) and aging (2%) and increased prevalence (22%) accounted for the increase.
In an accompanying editorial, Michael T. Lynskey, PhD, and John Strang, MBBS, FRCPsych, MD, both of King's College London, said the GBD has been important in demonstrating the effect of mental and substance use disorders, "and will hopefully be key not only in encouraging additional research into the prevalence and risks associated with these conditions but also in refining interventions and optimizing their implementation across both developed and developing countries."
For more information:
Degenhardt L. Lancet. 2013;doi:10.1016/S0140-6736(13)61530-5.
Lynskey M. Lancet. 2013;doi:10.1016/S0140-6736(13)61781-X.
Whiteford HA. Lancet. 2013;doi:10.1016/S0140-6736(13)61611-6 .
Disclosure: See the studies for a full list of financial disclosures.