Based on register data from 7,4 million persons living in Denmark between 1995 and 2015, the new nationwide study from the National Centre for Register-based Research at Aarhus BSS, Aarhus University, is the most comprehensive study ever done on mortality in persons with mental disorders.
"It is well known that people with mental disorders die earlier than the general population. However, for the first time, we present a comprehensive study where we investigate mortality in specific types of mental disorders. We have used new ways to measure life expectancy that are more accurate than the ones used in the past," says Dr. Oleguer Plana-Ripoll, who is a postdoctoral researcher at the National Centre for Register-based Research, Aarhus University, and the lead author of the study.
The results have just been published in The Lancet, which is one of the world's most prestigious medical journals.
The new study explores mortality for those with different types of mental disorders. The researchers were able to explore anonymous data within Danish health registers - the findings provide new insights into how mental disorders impact on the lives of people with disorders such as depression, anxiety disorders and substance use disorders.
"Most studies provide "mortality rates", which is a way to estimate the risk of death in those with mental disorders compared to those without. We investigated how mortality rates changed for each type of disorder, for each age, for males and females. In addition to looking at premature mortality, we were able to explore specific causes of death such as cancer, diabetes and suicide," says Oleguer Plana-Ripoll.
"The risk of an early death was higher for people with mental disorders across all ages," Oleguer Plana-Ripoll adds.
When looking at differences in life expectancy, the researchers found that men and women with mental disorders on average had life expectancies respectively 10 and 7 years shorter after the diagnosis of the disease compared to an overall Danish person of the same age.
"For example, people with depression or another type of mood disorder, which are among the most common mental disorders, had higher mortality rates. Apart from an increased risk of death due to suicide, we also confirm an increased risk of death due to somatic conditions such as cancer, respiratory diseases, diabetes etc. We found that men and women with mood disorders experienced life expectancies respectively 7.9 and 6.2 years shorter after disease diagnosis compared to the overall Danish person with the same age," says Dr Plana-Ripoll.
The study was completed as part of the Niels Bohr Professorship research programme at Aarhus University, which is led by Professor John McGrath. Funded by the Danish National Research Foundation, this research aims to explore innovative methods related to psychiatric epidemiology. According to John McGrath the research reveals worrying aspects of mortality among people with mental disorders.
"For example: we found an unusual pattern in men with a mental disorder. Contrary to our expectations, when we looked at life expectancy, they lost relatively few years of life due to cancer-related deaths compared to the general population. This was because, although they have a higher risk of dying from cancer, they are much more likely to die from cardiovascular and lung disorder at a younger age compared to the general population. This is a new and rather disappointing finding.", says Professor John McGrath.
"Our study emphasises the urgent need to improve general health for people with mental disorders, "John McGrath adds.