Mental illnesses are associated with a significantly increased risk of subsequent physical diseases, new research shows.
An international team of researchers has created an 'atlas' that maps the relationship between specific mental disorders and the risk of subsequent physical illnesses.
The researchers found that following the diagnosis of a mental disorder, psychiatric patients are significantly more likely than the general population to develop potentially life-threatening conditions, including heart disease and stroke.
These findings, investigators note, highlight the need for better medical care in this vulnerable population. They have created a website with detailed information about the risks of specific physical ailments and the link to particular mental disorders.
"We found that women with anxiety disorders have a 50% increased risk of developing a heart condition or stroke — over 15 years, one in three women with anxiety disorders will develop these medical disorders," lead investigator John McGrath, MD, PhD, University of Queensland's Brain Institute and Denmark's Aarhus University, said in a statement.
"We also looked at men with substance use disorders such as alcohol-related disorders and found they have a 400% increased risk of gut or liver disorders, while over 15 years, one in five of them will develop gut or liver conditions," he added.
The study was published online April 30 in the New England Journal of Medicine.
It's well known that patients with mental disorders have decreased quality of life, increased healthcare utilization, and a shorter life expectancy than individuals in the general population — about 10 years for men and 7 years for women.
However, the investigators note, previous research examining the relationship between mental disorders and medical conditions only focused on "particular pairs or a small set of mental disorders and medical conditions."
"We needed a comprehensive study to map the links between different types of mental disorders vs different types of general medical conditions. Our study has provided this atlas," McGrath told Medscape Medical News.
The clinical utility of such a map could provide comprehensive data on relative and absolute risks of various medical conditions after a diagnosis of a mental disorder.
This information, the researchers note, would "help clinicians and healthcare planners identify the primary prevention needs of their patients."
The study included 5.9 million people born in Denmark between 1900 and 2015 and followed them from 2000 to 2016, a total of 83.9 million person-years.
The researchers followed patients for up to 17 years (2000–2016) for medical diagnoses and up to 48 years (1969–2016) for diagnoses of mental disorders.
The study's large sample size allowed investigators to assess 10 broad types of mental disorders and 9 broad categories of medical conditions that encompassed 31 specific conditions.
Categories of medical conditions included circulatory, endocrine, pulmonary, gastrointestinal, urogenital, musculoskeletal, hematologic, neurologic, and cancer.
Mental disorder categories included organic disorders such as Alzheimer's, substance abuse disorders, schizophrenia, mood disorders, neurotic disorders, eating disorders, personality disorders, developmental disorders, behavioral/emotional disorders, and intellectual disabilities.
The researchers estimated associations between 90 pairs of mental disorders and broad-category medical conditions, as well as 310 pairs of mental disorders and specific medical conditions.
Individuals with mental disorders showed a higher risk of medical conditions in 76 out of 90 specific mental disorder–medical condition pairs.
After adjusting for sex, age, calendar time, and previous coexisting mental disorders, the median hazard ratio (HR) for a subsequent medical condition was 1.37 in patients with a mental disorder.
The lowest HR was 0.82 for organic mental disorders and the broad category of cancer (95% confidence interval [CI], 0.80 - 0.84), and the highest was 3.62 for eating disorders and urogenital conditions (95% CI, 3.11 - 4.22).
On the other hand, schizophrenia was associated with a reduced risk of developing musculoskeletal conditions (HR, 0.87; 95% CI, 0.84 - 0.91).
McGrath described this finding as "curious" and speculated it "may be related to underlying genetic risk factors."
One of the highest cumulative associations was for mood disorders and circulatory conditions during the first 15 years following a mood disorder diagnosis, compared with the matched reference group without a mood disorder (40.9% vs 32.6%, respectively).
The risk of developing subsequent medical conditions after a mental disorder diagnosis did not remain steady over time. For instance, although mood disorders were associated with an increased risk of developing circulatory problems (HR, 1.32 [1.31 – 1.34], the highest risk occurred during the first 6 months following diagnosis and gradually decreased over the next 15 years (HR 2.39 [2.29 – 2.48] and HR 1.18 [1.17 – 1.20], respectively).
"Many people with mental disorders have unhealthy lifestyle, including low exercise, poor diet, smoking, and alcohol, which may account for the increased risk of physical illness, and also they may not seek and/or may not get quick treatment for their health conditions," said McGrath.
Additionally, "perhaps some genetic and early life exposures, such as trauma, may increase the risk of both medical conditions and mental disorders," he added.
"We need better treatments for mental disorders, so that they do not slip into unemployment or poverty," McGrath added.
A Strong Case
Commenting on the study for Medscape Medical News, Roger McIntyre, MD, professor of psychiatry and pharmacology at the University of Toronto and head of the Mood Disorders Psychopharmacology Unit, University Health Network, Canada, said the research "really makes a strong case for the fact that persons who have mental disorders are at higher risk of chronic diseases, and it's the chronic diseases that decrease their lifespan."
McIntyre, who is also director of the Depression and Bipolar Support Alliance, said that the "take-away message is that mental disorders are not just brain disorders but are multisystem disorders."
For this reason, "the most appropriate way to provide care would be to provide a holistic approach to treat and prevent the chronic diseases that lead to increase in mortality," recommended McIntyre, who was not involved with the current study.
The study was supported by grants from the Danish National Research Foundation, the National Health and Medical Research Council, the Novo Nordisk Foundation , the European Union's Horizon 2020 Research and Innovation Program, the Aarhus University Research Foundation, the Lundbeck Foundation, the National Institutes of Health (NIH), the European Commission, Helsefonden, the Danish Council for Independent Research, the Independent Research Fund Denmark, the National Health and Medical Research Council of Australia, and the National Institute on Drug Abuse.
McGrath has disclosed no relevant financial relationships. The other authors' disclosures are listed on the original paper. McIntyre reports receiving grants from Stanley Medical Research Institute; the Canadian Institutes of Health Research/Global Alliance for Chronic Diseases/Chinese National Natural Research Foundation; and receiving speaking/consultation fees from Lundbeck, Janssen, Shire, Purdue, Pfizer, Otsuka, Allergan, Takeda, Neurocrine, Sunovion, and Minerva.
N Engl J Med. Published online April 30, 2020. Abstract
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Cite this: New 'Atlas' Maps Links Between Mental Disorders, Physical Illnesses - Medscape - May 11, 2020.