by Carol Cruzan Morton
25 May 2020
In one of the most comprehensive studies of its kind, an international team of researchers has strengthened the evidence that most mental disorders increase the risk of developing physical illnesses. They also showed that the medical risks varied by type of mental disorder in a new analysis of 5.9 million people in Denmark.
The paper reports that women with an anxiety disorder were 50 percent more likely to have a heart attack or stroke compared to those without. Men with a substance use disorder were 400 percent more likely to develop liver or gut problems. People diagnosed with schizophrenia, on the other hand, had a lower risk of later musculoskeletal disorders.
The study has immediate clinical application and also lays a foundation to explore the patterns in more detail to identify underlying causes and patterns. It was published April 30 in the New England Journal of Medicine.
“We needed a comprehensive study to map the links between different types of mental disorders versus different types of general medical conditions. Our study has provided this ‘atlas,’” said John McGrath of Aarhus University in Denmark and the Queensland Centre for Mental Health Research in Australia. McGrath and Aarhus colleagues Anders Prior and Natalie Momen led a team that encompassed expertise not just from Denmark and Australia, but from a number of other countries.
Danish data power
The study assessed 10 types of mental disorders and 9 categories of medical conditions of men and women living in Denmark from 2000-2016. The analyses combined de-identified medical data from three Danish national registries—in-patient and out-patient visits, prescriptions, and causes of death.
Nearly 12 percent had received a mental health diagnosis as early as 1969. The team conducted several hundred pair-wise statistical comparisons to determine the risk of different subsequent medical illnesses.
Previous research has reported earlier death among people with mental illness, which had been attributed in part to suicide. This study maps a wider range of physical illnesses to a broader swath of mental disorders.
There may be many explanations for increased physical illnesses, the authors speculate, including traumatic early life exposures, unhealthy lifestyles, delayed treatment for physical conditions, and possibly genetic factors.
“We hope that these findings, based on high-quality data, that we present in this study, can be used to inform clinicians, health care providers, and patients about the most common co-morbidities for people with mental disorders,” said first author Momen.
Future studies will assess how mental disorders plus general medical conditions affect premature mortality. “We want to develop innovative methods in psychiatric epidemiology,” McGrath says. “Part of this relates to understanding patterns of comorbidity.”
“Denmark has a long tradition of excellent health registers. With appropriate governance and ethical permissions, researchers can explore health-related questions in de-identified Danish health registers, said McGrath. “It is a great privilege to have access to these data, and we hope that our research can lead to better outcomes for people with serious mental disorders”
The team created a data visualization site for others to interrogate the date in multiple ways. Two statistical models adjust for sex, age, and other types of mental disorders. Model B is more useful for clinicians, McGrath says. Two weeks after the paper was published, McGrath counted 2300 visits from 85 countries to the interactive site.
Momen NC, Plana-Ripoll O, Agerbo E, Benros ME, Børglum AD, Christensen MK, Dalsgaard S, Degenhardt L, de Jonge P, Debost JPG, Fenger-Grøn M, Gunn JM, Iburg KM, Kessing LV, Kessler RC, Laursen TM, Lim CCW, Mors O, Mortensen PB, Musliner KL, Nordentoft M, Pedersen CB, Petersen LV, Ribe AR, Roest AM, Saha S, Schork AJ, Scott KM, Sievert C, Sørensen HJ, Stedman TJ, Vestergaard M, Vilhjalmsson B, Werge T, Weye N, Whiteford HA, Prior A, McGrath JJ. Association between Mental Disorders and Subsequent Medical Conditions. N Engl J Med. 2020 Apr 30;382(18):1721-1731. PubMed