The idea that what goes on in our heads can profoundly affect our body’s typical functions has gained momentum over time, with decades of research revealing how gut health can affect mood and even neurological conditions.
A new study by a team of researchers from Australia now suggests that mental illness may manifest even more clearly in the body than in the brain. An analysis of more than 175,000 individuals suggests that poor physical health scores may be a better indicator of mental illness than changes detected on brain scans.
Lead author, psychiatrist and neuroscientist Ye Ella Tian, explained on Twitter that those diagnosed with mental illness showed subtle brain changes, as you might expect, but they also had “significantly worse physical health across multiple body systems compared to their healthy peers.”
In some ways, this isn’t too surprising. Research shows that mental illness is linked to poor physical health and chronic diseases, such as obesity and diabetes, which may be related to the side effects of medication or differences in access to healthcare.
For example, people with schizophrenia are about three times more likely to develop diabetes than the general population; they also have a two-fold increased risk of coronary heart disease, says Tian.
However, the impact of serious mental illness on other aspects of physical health, such as lung health, liver dysfunction and bone loss, is less well studied. To make matters worse, physical health more generally has been “underestimated, under-treated and often overlooked in psychiatry” for decades, according to Tian and colleagues at the University of Melbourne. to write.
Putting together a series of measurements from MRI brain scans and health assessments from a number of different research collectives, the team produced scores of brain health and the function of seven body systems, including the immune system, liver (liver) function, heart, lung and kidney health. This allowed them to compare the health scores of people diagnosed with mental illness to populations of people of the same age.
Differences in brain imaging results can accurately differentiate between the four mental illnesses studied: schizophrenia, bipolar disorder, depression, and generalized anxiety disorder.
And yet, despite the neural basis of mental illness, the study found that individuals with one or more of these disorders could be differentiated “with modest accuracy” of healthy controls of a similar age, based only on body health.
Body health scores for liver and kidney function, immune system, and metabolism were consistently poor compared to healthy controls — and found to be better predictors of a mental health diagnosis than brain imaging scores.
That physical health measures would outweigh differences in brain imaging results “was quite a surprising finding” given how mental illness is rooted in the disordered brain, University of Melbourne neuroscientist Andrew Zalesky said. explained in a podcast.
Still, there are many possible reasons that explain why poor physical health goes hand-in-hand with serious mental illness: from the side effects of antipsychotics and mood-stabilizing drugs to the chronic stress, increased infections, and improved immune responses experienced by people with mental health problems. . For example, research shows that for people with schizophrenia, their risk of dying from COVID-19 was nearly three times higher than for people without the disorder.
The researchers note that their findings – which mostly come from white, British populations – are not intended to be used as a diagnostic tool. “We should note here that these are individuals with an established diagnosis,” Zalesky added. “We don’t know if this would apply to the onset of the disorder.”
Instead, the findings should help psychiatrists understand how different aspects of physical health are affected by mental illness, and encourage them to consider both the body and mind when treating people with mental illness.
In this particular study, chronic physical health problems often went undiagnosed in people with mental illness, but the findings suggest “that poor body health and function may be important disease manifestations that require ongoing treatment in patients,” the researchers said. to conclude.
The study is published in JAMA Psychiatry.