Mental Disorders Leading Cause of Nonfatal Illness Worldwide

Caroline Cassels

August 28, 2013


Mental and substance use disorders are the leading cause of nonfatal illness worldwide, with a global disease burden that trumps that of HIV/AIDS, tuberculosis, diabetes, or transport injuries, new research shows.

A team of investigators from the United States and Australia led by Professor Harvey Whiteford found that in 2010, mental and substance use disorders were the fifth leading contributor to death and disease worldwide and that at 40%, depressive disorders account for the largest proportion of this burden.

"Mental and substance use disorders are major contributors to the global burden of disease and their contribution is rising, especially in developing countries. Cost-effective interventions are available for most disorders but adequate financial and human resources are needed to deliver these interventions," Professor Whiteford, Queensland Centre for Medical-Health Research, University of Queensland, Australia, said in a statement.

The results of the Global Burden of Diseases, Injuries and Risk Factors Study (GBD 2010) are published online August 29 in The Lancet.

Biggest Disability Burden in the Young

Historically, the researchers note, psychiatric disorders have not been a global health priority. In addition, previous estimates of the global burden of mental illness have been hampered by incomplete data that have not taken all psychiatric and substance use disorders into account.

The current number of specific mental and substance use disorders has been expanded in the GBD study to reflect updated epidemiologic evidence for certain disorders.

The GBD 2010 study included 20 disorders that consisted of all anxiety disorders, eating disorders, childhood behavioral disorders, pervasive developmental disorders, and idiopathic intellectual disability in 187 countries.

The aim of the study was to "summarize fatal, non-fatal, and total burden for 11 classes of mental and substance use disorders for 2010 with reference to changes in burden since 1999."

The investigators used data from GBD 2010 to estimate the burden of disease attributable to mental and substance use disorders in terms of disability-adjusted life-years (DALYs), years of life lost to premature mortality, and years lived with disability (YLDs).

When the researchers analyzed the contribution of mental and substance disorders to nonfatal illness only, they found they were responsible for more than a fifth (22.8%) of all disease burden, the leading cause worldwide.

The researchers found that mental and substance use disorders were the leading cause of YLDs worldwide. Depressive disorders accounted for 40.5% of DALYs caused by mental and substance use disorders, with anxiety disorders accounting for 14.6%, illicit drug use disorders for 10.9%, alcohol use disorders for 9.6%, schizophrenia for 7.4%, bipolar disorder for 7.0%, pervasive developmental disorders for 4.2%, childhood behavioral disorders for 3.4%, and eating disorders for 1.2%.

The researchers also report the highest proportion of DALYs occurred in people aged 10 to 29 years.

Mental Illness Burden Higher in Females

Girls and women had a greater burden of death and disease from mental disorders than boys and men. However, men had a greater burden from drug and alcohol dependence.

According to investigators there were significant differences between world regions for some of the disorders analyzed, with eating disorders showing the greatest overall variation.

China, North Korea, Japan, and Nigeria had burdens of death and disease from mental and substance disorders that were statistically lower than the global average.

"Despite 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.

"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," said Professor Whiteford.

The authors have disclosed no relevant financial relationships.

Lancet. Published online August 29, 2013.


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