People With Mental Illness Feel Physical Symptoms Differently, Here’s Why

People who live with mental health conditions experience physical signals differently, according to research published in The American Journal of Psychiatry. 

“The biggest takeaway from our research is that regardless of what someone’s mental ill-health looks like—high anxiety, anorexia, depression, and so on—there is a common difference in the way their brains process physical signals from the body,” lead author Camilla Nord, PhD, a neuroscientist at the University of Cambridge, tells Verywell. 

Nord and a team of researchers analyzed brain imaging data from existing studies and then compared it with research they conducted on over 1,200 participants.

The Study

During their research, they looked at the brain activity of 626 people with mental health disorders and 610 people without mental health conditions. 

The researchers specifically studied how the participants’ brains processed interoception—the ability to sense conditions in the body. 

“Interoception is our brain’s way of listening to the body: Am I thirsty? Hungry? In pain? By using interoception to listen to the body, our brain helps us survive, leading us to eat when we’re hungry, or avoid things that cause us pain,” explains Nord. 

Julian Lagoy, MD, a psychiatrist with Community Psychiatry, explains that while people are familiar with how they perceive the outside world through sight, smell and touch, interoception refers to how people perceive things within their body. 

“This connects well with mental health conditions because mental illness does affect our interoception. Those with mental illness perceive internal conditions in the body differently than those without,” he says.

Nord points out that for a long time, scientists have appreciated that people with mental health conditions show differences in interoception.

“For example, people who experience anxiety are more likely to report feeling dangerous sensations in the body (fast heart-rate, dizziness, and so on). In fact, many core symptoms of mental health disorders, from disrupted appetite to fatigue to diminished sex drive, come from our brain’s interpretation of the body, i.e., interoception),” Nord says.

However, her research pinpointed where these differences in interoception come from. Nord observed differences in activity in the part of the brain called the dorsal mid-insula in people without mental health disorders compared to people with a variety of mental health disorders, including depression, schizophrenia, eating disorders, and anxiety disorders. 

“This experiment adds to decades of experiments showing that physical and mental health are interconnected. One way physical and mental health could be interconnected is via changes in one particular brain region, the mid-insula, which is involved in interpreting the physical state of the body,” says Nord. 

Connection Between Physical and Mental Health

Lagoy believes Nord’s research shows how our physical and mental health are connected and
reliant on each other.

“It is unfortunate that we regularly separate physical and mental health, because at the end of the day it is all one and the same,” Lagoy says. 

Nord agrees, noting that people often assume that what they feel physically is an exact, accurate representation of what is going on in their body—whether that is pain, hunger, thirst, etc. 

“But actually, these feelings in the body can only ever be felt via the brain, which means they are inevitably affected by many other factors, such as the environment you are in, whether you’ve recently been reminded about pain/food, and so on,” she says. 

Additionally, Nord says the brain can physically change the activity of parts of your body. For instance, have you ever felt nauseous when you’re actually just nervous? 

“[This] means there is both a route from the body influencing the brain, and a route from the
brain influencing the body. Both of these routes help keep us healthy and alive,” Nord says. 

More research about the brain and its function and the correlation between physical and mental health is needed, says Lagoy. 

“We are only just beginning to understand how the brain works… Doing more research in this area will greatly improve treatments in mental health and greatly help us understand the most complex organ in the body: the brain,” he says. 

Laying Groundwork for Better Treatments

Previous research has showed differences in interoceptive processes of those mental health conditions, such as eating disorders, anxiety and depression, panic disorder, addiction and more. 

And because Nord’s study shows that the difference in activity in the mid-insula in mental health disorders does not overlap with portions of the brain typically changed by antidepressant medication or psychological therapy, she believes this discovery could help in developing more targeted and effective treatments for mental health conditions, such as brain stimulation. 

“[There] may be other treatments that affect this region, or new treatments that could be developed to target brain cell activity in this region, which is something I would like to work on,” Nord says. 

As someone who treats people with mental health conditions, Lagoy finds hope in this discovery. 

“Medications cause a chemical and physical change in our brain and understanding the connection between physical and mental health will greatly optimize medication treatment in treating mental health,” he says.