Researchers used data from the UK biobank to investigate the link between mental illness and biological ageing
“Our findings indicate that the bodies of people with mental health problems tend to be older than would be expected for an individual their age. This may not explain all the difference in health and life expectancy between those with mental health problems and the general population, but it does mean that accelerated biological ageing may be an important factor." Dr Julian Mutz, postdoctoral research associate, King's College London
People with a lifetime history of mental disorders such as anxiety, depression or bipolar have blood markers suggesting they are up to two years older than their actual age, a study has found.
The study, carried out by Dr Julian Mutz and Professor Cathryn Lewis of King’s College London, examined data on 168 different blood metabolites (products of metabolism) from 110,780 participants in the UK Biobank. They linked this data to patient records, which showed whether individuals had a history of mental illness, and found that those with a mental illness had a metabolite profile older than would have been expected for their age.
Mutz, the lead researcher on the study, told the European Congress of Psychiatry in Paris, that it was now possible to predict people’s age from blood metabolites. He added: “We found that, on average, those who had a lifetime history of mental illness had a metabolite profile which implied they were older than their actual age. For example, people with bipolar disorder had blood markers indicating that they were around two years older than their chronological age.”
It is already known that people with mental health disorders tend to have shorter lives, and poorer quality health, than the general population. People with poor mental health show an increased tendency to develop conditions such as heart disease and diabetes, and these conditions tend to worsen with age. A 2019 study found that on average people with mental disorders had shorter life expectancy (in comparison to the general population) by 10 years for men and seven years for women. The King’s research suggests that this is because mental health is linked to accelerated ageing.
Mutz said: “Our findings indicate that the bodies of people with mental health problems tend to be older than would be expected for an individual their age. This may not explain all the difference in health and life expectancy between those with mental health problems and the general population, but it does mean that accelerated biological ageing may be an important factor. If we can use these markers to track biological ageing, this may change how we monitor the physical health of people with mental illness and how we evaluate the effectiveness of interventions aimed at improving physical health”.
Speaking to the Telegraph, Mutz said that the differences were largest for people with bipolar disorder (about two years) and smallest for people with anxiety disorder (0.7 years). Depression was somewhere in between: “The finding that these differences were greatest in people with bipolar disorder is something that we also observed for other measures of biological ageing, for example when looking at frailty.”
He added that while the data did not prove causation, it opened up avenues for future research. “There are several plausible pathways linking psychiatric disorders to accelerated biological ageing,” he said. “For example, lifestyle (e.g., physical inactivity, higher rates of smoking), biology (e.g., overactivation of the autonomic nervous system, chronic low-grade inflammation) and psychosocial factors (social isolation, loneliness) in people with mental illness likely negatively impact biological ageing and their health, highlighted by the higher prevalence of age-related diseases and lower life expectancy compared to the general population.
“I would speculate that it is a mutually reinforcing process, i.e. mental illness negatively impacts ageing, and faster biological ageing and poor health in turn negatively impacts mental health.”
Dr Sara Poletti of the Istituto Scientifico Universitario Ospedale San Raffaele, Milan, said that the work was important because “it gives a possible explanation for the higher prevalence of metabolic and age-related diseases in patients with mental illness.” She added: “Understanding the mechanisms underlying accelerated biological ageing could be crucial for the development of prevention and tailored treatments to address the growing difficulty of an integrated management of these disorders”.
This is a highly interesting study that demonstrates the value of the UK Biobank for medical researchers. We have long known that people with mental illness tend to die younger than the rest of the population, but it has not been clear why. This research showing that the bodies of people with mental illness appear to be ageing faster is the first step to greater understanding of the mechanisms by which mental illness may lead to early death. There is still much work to be done, however, to investigate the pathways by which psychiatric disorders may lead to faster biological ageing.