The findings, based on an extensive review of the evidence, indicate that mental disorders are among “the most substantial causes of death worldwide” — claiming about 8 million lives each year and cutting potential life spans short by roughly a decade, the researchers conclude.
The link between mental illness and early death is well documented, with some studies suggesting that mental disorders such as schizophrenia can shorten the lifespan as much or more than smoking. But the new meta-analysis — believed to be the largest study on the topic to date — revealed just how widespread the problem is for anyone struggling with a mental disorder, including common conditions like depression and anxiety.
“These estimates suggest that mental disorders rank among the most substantial causes of death worldwide,” the researchers write. “Efforts to quantify and address the global burden of illness need to better consider the role of mental disorders in preventable mortality.”
Mortality gap linked to underlying inequities in health, health care
The study was led by Elizabeth Reisinger Walker of Emory University in Atlanta. She and colleagues conducted a review of 2,481 studies that looked at the association between mental health disorders — including depression, anxiety, schizophrenia and bipolar disorder — and mortality.
The researchers included 203 studies in their final analysis, which represented 29 countries over six continents. These studies either compared the mortality risk of people with mental health disorders against that of the general population or people without mental illness.
The risk of mortality from all causes, they found, was 2.2 times higher for people with mental-health disorders than it was for people without mental-health disorders. In other words, those with mental illnesses were twice as likely to die from any given particular cause — cancer or diabetes, for examples — than were the rest of the population. This resulted in an average of 10 years of potential life lost among people with mental illness.
The study also found that, among those with mental disorders, 67.3 percent of deaths were attributable to natural causes and 17.5 percent of them to unnatural ones, with the causes of the remaining 15.2 percent unknown. In addition, the researchers calculated that each year, around 8 million (14.3 percent) deaths worldwide are attributable to mental illness.
About one in four adults in the U.S., or 61.5 million people, will deal with mental illness in any given year, according to the National Alliance on Mental Illness. Around one in 17, or roughly 13.6 million people — live with serious disorders such as bipolar disorder or schizophrenia.
The fact that most deaths reviewed by the study were attributed to natural causes indicate that having a mental disorder might have an impact on one’s ability to access or obtain health care that could successfully treat or at least mitigate these causes, the authors said. People with mental health disorders also tend to have higher rates of chronic disease risk factors, including tobacco smoking, substance abuse, physical inactivity, and poor diet.
“People with mental disorders often do not receive preventive services, such as immunizations, cancer screenings and tobacco counseling, and often receive a lower quality of care for medical conditions,” the researchers wrote. “Efforts must be made to prevent and manage comorbid medical conditions and reduce the occurrence of unnatural deaths in this vulnerable population.”