Overall mental disorder diagnosis may increase likelihood of medical diagnoses

Most, but not all, mental disorders are associated with an increased risk of medical conditions — although the extent of that risk is attenuated by the age at which the mental disorder is diagnosed, as well as the gender of the person diagnosed.

A notable exception to this pairing of mental and medical condition is schizophrenia: a diagnosis of schizophrenia appears to reduce the risk of musculoskeletal conditions such as rheumatoid arthritis, wrote Natalie C. Momen, PhD, of the National Center for Register-based Research, School of Business and Social Sciences, Aarhus University, Aarhus, Denmark, and colleagues in The New England Journal of Medicine.

“The absolute risk of a medical condition within 15 years after a mental disorder was diagnosed varied from 0.6% for a urogenital condition among persons with a developmental disorder to 54.1% for a circulatory disorder among those with an organic mental disorder,” they wrote.

The Danish national registry includes data from 5.9 million persons born in Denmark from 1900 through 2015, and followed them from 2000 through 2016. “We assessed 10 broad types of mental disorders and 9 broad categories of medical conditions (which encompassed 31 specific conditions). We used Cox regression models to calculate overall hazard ratios and time-dependent hazard ratios for pairs of mental disorders and medical conditions, after adjustment for age, sex, calendar time, and previous mental disorders.” Median ages ranged from early 30s at entry into the cohort to late 40s at the last follow-up.

Among the findings:

  • Globally, mental disorder diagnoses carried an increased relative risk of being diagnosed with a medical condition.
  • HR for association between a mental disorder and a medical condition was 1.37.
  • Organic mental disorders and “the broad category of cancer” had the lowest HR—0.82 (95% CI 0.80-0.84).
  • A diagnosis of eating disorder carried a relative risk of 3.62 for urogenital conditions (95% CI 3.11-4.22).

“In competing-risk analyses, the cumulative incidences of diagnoses of medical conditions within 15 years were higher among persons who had received a diagnosis of a mental disorder at a younger age. In older persons, the cumulative incidence of selected medical conditions was often lower among those in whom a mental disorder had been first diagnosed after the age of 60 years than among those in the reference group,” they wrote.

Momen and colleagues noted that the finding on cancer — overall a lower risk for those diagnosed with a mental disorder — was puzzling since persons diagnosed with mental illness are often more likely to smoke, have poor cardiovascular conditioning, and be obese, all of which are risk factors for cancer. Moreover, in earlier studies, this group found that “men with mental disorders had a higher risk of dying from cancer than men without mental disorders but were less likely than the general population to die prematurely from cancer. This finding probably reflects the shortened survival of these men as the result of other medical conditions (e.g., circulatory diseases).”

The authors cautioned that they were not proposing “a causal relationship between mental disorders and subsequent medical conditions. The presence of both a mental disorder and a medical condition may be confounded by previous exposures (e.g., substance use, childhood abuse, socioeconomic factors, and shared environmental risk factors) or shared genetic factors. Mental disorders affect lifestyle, daily habits, and socioeconomic status, which in turn may mediate the risk of subsequent medical conditions.”

They also noted a number of limitations to the study, including the decision to limit to a relatively small group of medical conditions and to exclude accidents, injuries and acute conditions. They also did not consider “the full spectrum of coexisting conditions because patients may have multiple mental disorders and multiple medical conditions.” Finally, they noted that the findings may not be generalizable outside of Denmark.

  1. Be aware that this cohort study of registry data describes associations between diagnosis of mental disorders and risk for medical conditions, but the findings do not support causality.

  2. Note that the age at diagnosis of mental disorders appears to be related to absolute risk of medical conditions, with older age at diagnosis of mental disorder carrying the greatest risk.

Peggy Peck, Editor-in-Chief, BreakingMED™

Momen had no financial dislosures.

Cat ID: 146

Topic ID: 87,146,838,914,187,111,188,192,146,479,54,55,57,925