Mental illness is a notorious thief, stealing joy, peace, and ease from the estimated one billion people worldwide who suffer from it. Now, it appears that mental illness steals still more too: years and youth. According to new research presented Mar. 26 at the European Congress of Psychiatry in Paris, people suffering from a range of psychiatric conditions—particularly depression, bipolar disorder, and anxiety—carry markers in their blood indicating that their biological age is older than their chronological age.
The findings, presented by Julian Mutz, a post-doctoral research associate at King’s College London, were based on a robust survey he and his colleagues conducted of more than 110,000 blood samples maintained at the UK Biobank, a large-scale biomedical database containing blood and genetic samples from more than half a million U.K. residents. The samples are cross-indexed with the donors’ age, gender, and medical history, providing a detailed portrait of the overall health of a representative sampling of the U.K. population.
Mutz and his colleagues used the biobank data to study blood for 168 different metabolites, including cholesterol, fatty acids, inflammatory markers, and more, all of which can indicate a person’s biological age. “Some of those markers increase with age,” says Mutz, “some decrease, and some have a nonlinear relationship, so they would increase for a number of years [and then decrease].”
Among the key metabolites Mutz and his colleagues studied were creatine, an amino acid involved in muscular health, which tends to decrease with age; fatty acids, which also decrease with age; and the inflammatory markers known as c-reactive proteins, which can be indicators of declining heart health. The researchers then compared the blood analyses to the records of the patients’ age, as well as to baseline questionnaires they answered between 2006 and 2010 regarding their mental health and whether they’d ever been diagnosed with any clinical condition. The data in the biobank is also linked to primary care records and hospital inpatient records.
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The results of all of this analysis were striking. On the whole, Mutz found, patients with bipolar disorder had a biological age that was two years greater than their calendar age. For depression, it was one year older, and for anxiety conditions it was 0.7 years older. “This helps explain why, at least on average, people with mental health disorders tend to have a higher prevalence of age-related diseases,” such as heart disease and diabetes, Mutz says.
Multiple large population studies, including one of nearly 7.4 million people that appeared in the Lancet in 2019, have found that men who suffer from mental health conditions have a 10-year shorter life expectancy than the general population; for women, it’s seven years shorter.
“The estimates differ a little bit depending on the diagnosis,” Mutz says. “For example, people with schizophrenia or a psychosis have a greater difference in terms of life expectancy than people with depression or anxiety.”
Going forward, Mutz hopes that his findings can help researchers gauge the effectiveness of mental-health interventions, using ongoing blood studies of people receiving psychiatric therapy to help determine how effective the treatment is.
“I could imagine a randomized control trial where we look at, say, exercise, which is very helpful for physical health and mental disorders,” says Mutz, “and see if it improves overall biological aging. Keeping track of these molecular aging clocks can be useful in providing care.”
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