Individuals with a history of hospitalisation for substance use disorders had considerably worse results following the onset of a wide range of physical health illnesses, according to experts from the UK and Czechia.

In a study published on November 7 in The Lancet Psychiatry, researchers looked at the risk of mortality and loss of life-years among people who developed 28 different physical health conditions, comparing those who had previously been hospitalised with substance use disorder against those who had not.

They found that patients with most of the health conditions were more likely than their counterparts to die during the study period if they had been hospitalised with substance use disorder prior to the development of these conditions.

For most subsequent health conditions, people with substance use disorders also had shorter life expectancies than individuals without substance use disorders. According to UK and Czechia experts, people with a history of hospitalisation for substance use disorders had considerably worse results following the onset of a wide range of physical health illnesses.

Although the study only looked at people living in Czechia, the researchers believe the results are likely to be similar in other countries, too.

They found that people with pre-existing substance use disorders were more likely than their counterparts to have died during the study following the development of 26 out of 28 physical health conditions.

For seven of these conditions - including atrial fibrillation, hypertension, and ischaemic heart disease - the risk was more than doubled. In most cases, people with substance use disorders have shorter life expectancies than their counterparts.

Lead author Tomas Formanek, a PhD student at the National Institute of Mental Health, Czechia, and the University of Cambridge, said: "Substance use disorders seem to have a profound negative impact on prognosis following the development of various subsequent physical health conditions, in some cases dramatically affecting the life expectancy of the affected people."

It is not clear why this should be the case, though the researchers say there are a number of possible reasons. It is already known that substance use has a direct negative impact on physical health and is associated with lifestyle factors that affect our health, such as smoking, lack of exercise, and poor diet.

Similarly, people with substance use disorders are less likely to take part in screening and prevention programmes for diseases such as cancer and diabetes and are less likely to use preventive medication, such as drugs to prevent hypertension.

There are also some factors not directly related to substance use, such as diagnostic overshadowing, meaning the misattribution of physical symptoms to mental disorders. Such misattribution can subsequently contribute to underdiagnosis, late diagnosis, and delayed treatment in affected individuals.

Senior author professor Peter Jones from the Department of Psychiatry, University of Cambridge, added: "These results show how important it is not to compartmentalise health conditions into mind, brain or body. All interact leading here to dramatic increases in mortality from subsequent physical illnesses in people with substance use disorders. There are clear implications for preventive action by clinicians, health services, and policy developers that all need to recognise these intersections."

Co-author Dr Petr Winkler from the National Institute of Mental Health, Czechia, said: "It is also important to consider that the majority of people with substance use disorders go undetected. They often do not seek professional help and hospitalisations for these conditions usually come only at very advanced stages of illness. Alongside actions focused on the physical health of people with substance use disorders, we need to equally focus on early detection and early intervention in substance use disorders."