Mental disorders increase the risk of subsequent general medical conditions

Breaking new ground 5. jun 2020 3 min Postdoc Anders Prior Written by Morten Busch

More than 10% of people have a diagnosed mental disorder that worsens their quality of life to some extent and often reduces how long they live. This probably results from a much higher prevalence of general medical conditions (also called physical or somatic conditions). New research shows that people with mental disorders are 37 % more likely to develop a general medical condition and that 76 of 90 pairs of mental disorders and general medical conditions occur more frequently. The increased prevalence probably results from the mental symptoms drowning out the physical symptoms, so that both doctors and patients overlook the danger signals.

What some people experience as strong physical pain may be overlooked by others as insignificant. Severe mental disorders can sometimes be so overwhelming that the people affected do not notice the body’s danger signals telling them that something is wrong. This may include minor physical illnesses but also serious life-threatening diseases such as cancer or cardiovascular diseases. The largest study of the prevalence of general medical conditions among people with mental disorders has been published in The New England Journal of Medicine.

“The overarching conclusion is that people with mental disorders have 37% more general medical conditions. These were not a few distinct associations between specific mental disorders and general medical conditions. As many as 76 of the 90 associations with general medical conditions we examined showed an increased prevalence among people with mental disorders. This suggests that doctors should probably pay more attention to physical symptoms of these people and that we as a society should probably practice giving more to those most in need,“ explains an author, Anders Prior, general practitioner, postdoctoral fellow and part-time lecturer, Research Unit for General Practice and Department of Public Health, Aarhus University.

Surprisingly many associations

The researchers used a population-based cohort from Denmark’s nationwide registries that included data on more than 5.9 million people born in Denmark from 1900 through 2015 and followed them from 2000 through 2016 – for a total of 83.9 million person-years.

The goal was to try to create a visual atlas. The researchers therefore assessed 10 broad types of mental disorders and 9 broad categories of general medical conditions, which encompassed 31 specific conditions – ranging from diabetes to cancer.

After adjusting the data for age, sex, calendar time and previous mental disorders, the researchers calculated both the relative and absolute risk of each general medical condition and compared this between people with and without a mental disorder.

“Some obvious associations were not altogether surprising, such as the association between substance abuse disorders and diseases of the liver and intestines, with the risk being more than 3 times greater. What was surprising, in contrast, was clear associations between virtually all mental disorders and general medical conditions,“ says Anders Prior.

Doctors should pay greater attention

There are only a few general medical conditions that people with a mental disorder are less likely to have. People with an organic mental disorder in which, for example, a head injury or a mental disorder such as Alzheimer’s disease influences their thoughts, feelings or behaviour, have a lower risk of developing cancer.

“The study may seem like positive news, but unfortunately it does show that people with mental disorders generally die earlier from general medical conditions such as cardiovascular diseases. In a wider context, this is disturbing information in every way for people with a mental disorder,“ explains Anders Prior.

According to Anders Prior, this information should also lead to changes in how the healthcare system treats people with mental disorders.

“One reason for the hefty numbers is that people with mental disorders notice general medical conditions less often because these conditions are simply overwhelmed by the severe mental health problems. However, this should also encourage doctors to pay more attention when they encounter people with mental disorders,“ says Anders Prior.

Perhaps also wear and tear on the body

This is where the new visual atlas can really come into its own. The atlas is intended to and can be used as a tool in the dialogue between doctors and patients, so that doctors can discuss and enquire about specific symptoms within the various categories and thereby discover conditions that would otherwise go unnoticed.

“We talk a lot about the desire for equality in health, and there is undoubtedly much to be gained here, since there is significant social inequality in the prevalence of mental disorders. So here we really have the opportunity to help the people who need it the most,“ explains Anders Prior.

Since mental disorders typically develop early, whereas general medical conditions develop later in life, Anders Prior even expects that the difference would probably be even greater if these people were followed for even more years than was possible in this study. However, it is too early to say whether underdiagnosis means that people with mental disorders develop serious general medical conditions.

“Undoubtedly, they visit doctors less, and doctors probably also discover fewer general medical conditions in this group. However, there are also some theories about allostatic load, suggesting that the wear on tear on the bodies of people living with stressful mental disorders over many years actually manifests itself physiologically through changes in signalling pathways and the like that can eventually lead to a severe general medical condition,“ says Anders Prior.

Association between mental disorders and subsequent medical conditions” has been published in The New England Journal of Medicine. In 2018, the Novo Nordisk Foundation awarded a grant to Anders Prior for the project Complex Multimorbidity and Healthcare Pathways in General Practice. In 2016, the Foundation awarded a grant to Søren Dalsgaard for the project Polygenic Risk Scores and Early Social Adversities in Predicting the Developmental Course and Trajectory in Individuals with ADHD and a grant to Anette Riisgaard Ribe for the project Prognosis of Elderly Persons with Mental-physical Multimorbidity.

During the course of a year, approximately 90% of the Danish population are in contact with their general practitioner. Thus, general medicine is cent...

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