Study Links Depression to More Physical Health Issues

People with a history of depression are more likely to develop a host of physical health issues—and get them at a faster rate—compared to those who don’t live with the mental health disorder, a new study suggests.

Published in PLOS Medicine on Feb. 13, the research is based on data from over 172,500 people enrolled in the U.K. Biobank study. Volunteers ranging in age from 40 to 71 completed a baseline health assessment and were then followed for an average of about seven years.

Researchers found that the 30,770 participants with depression reported having an average of three physical health conditions, while people without depression had an average of two.

Additionally, those with depression accumulated a new condition about every five years, compared to every 6.25 years for the non-depression group. Looking at participants who were the same age and sex, those with a depression diagnosis developed these long-term health issues at a 30% faster rate.

The most commonly reported conditions were high blood pressure, allergies, osteoarthritis, and gastroesophageal reflux disease. All of these were more common in people with depression, as were sleeplessness, chronic pain, obesity, smoking, loneliness, and stressful life events.

“[Other] studies have shown that people with depression have more long-term physical health conditions, but they can’t tell us which came first,” said lead study author Kelly Fleetwood, MSc, a statistician at the University of Edinburgh.

Though it’s likely that physical ailments worsen mental health, it’s clear from the design of this study that having depression does put a person at a greater risk of developing physical conditions as they age, Fleetwood told Health.

This is significant, as depression affects about 280 million people globally.

According to the researchers, the findings suggest depression should be thought of as a “whole body” condition, given its significant connections to other aspects of physical health. This means providers should offer “additional support to help people with depression improve their physical health,” Fleetwood said.

Physical symptoms, including fatigue, discomfort, and pain, often accompany depression, said Bruce Guthrie, MSc, PhD, study co-author and professor of general practice at the University of Edinburgh. However, “the mechanism for this isn’t known,” he said.

Similarly, though this study found that people with depression seem to develop more physical health issues, it can’t fully explain why, Mary de Groot, PhD, professor of medicine and associate vice chair of wellness at the Indiana University School of Medicine, told Health.

That being said, experts agreed that lifestyle behaviors associated with depression likely play some role.

“Many people who are depressed become less physically active, partly because they often withdraw from social and other activity, or lose the motivation to exercise as much,” Guthrie told Health. “Eating patterns and how much alcohol people drink may also change when depression is active.”

These changes in sleep, exercise habits, diet patterns, and social activity make it hard for people with depression to stick to “self-care behaviors that promote good health and are protective from long-term diseases,” said de Groot.

However, it’s not clear if this fully explains the connection, or if depression impacts physical health in other ways, Guthrie said. There are other “drivers of depression” that could be affecting the body’s organ systems, added de Groot.

One is inflammation, which has been linked to a wide range of conditions, including depression, diabetes, and cardiovascular disease, she said.

“Genetic susceptibility is another common factor that may underlie these relationships,” de Groot explained. Some people might have a genetic predisposition that causes them to develop depression and some of these other health conditions, she said. However, more research is needed to investigate this theory.

Though “the current study helps to establish that depression is a risk factor for a wide array of physical conditions,” de Groot said, it’s also true that physical ailments can impact mental health.

“People who develop physical conditions are more likely to become depressed, which again, might be because of shared mechanisms or might be because of the ‘biographical disruption’ that becoming chronically physically ill brings,” Guthrie said.

For example, these “disruptions” could be shocks to one’s perceived identity or changes to their social life or work after becoming sick, he explained.

The link between depression and physical health is likely a “bidirectional relationship,” de Groot said. Importantly, this study points to the “mind-body connection” and is yet another piece of evidence that mental and physical conditions aren’t separate but rather are “deeply interconnected,” she said.

“For example, we have ample evidence that a lifetime history of depression increases the risk of developing type 2 diabetes,” de Groot said. “Likewise, a history of diabetes increases the risk of developing later depression.”

It’s a similar story in cardiovascular medicine, she explained, where researchers have discovered that depression can crop up both before and after cardiac events.

As with any study, there are some limitations to this new research. Chiefly, the volunteers who chose to participate in the U.K. Biobank study are “a healthier group of people overall,” Fleetwood said, which means that the results may not be the exact same if the researchers surveyed the U.K. population at large.

Still, with such a large sample size, the study’s results likely hold up for the average person, de Groot said.

That means that because depression has been associated with so many health conditions—including osteoarthritis, hypertension, and diabetes—it’s important that people share any mental health concerns with a clinician.

“If you are experiencing changes in your mood—like feeling down, depressed, persistently sad—having a lack of interest in activities you would ordinarily enjoy, experiencing changes in sleep, appetite, unintentional weight gain or loss, changes to your ability to concentrate, and/or thoughts of death, these are important symptoms to share with your primary care or other health care provider,” said de Groot.

Information on your mental health is as crucial as any other physical health marker, and it needs to be taken seriously so you can get the care you need, she stressed.

There are a host of depression treatment options out there, including medications and counseling, de Groot said.

Plus, many of the lifestyle modifications you might take on to treat depression often dovetail with those that improve your physical health, Guthrie added.

This includes drinking alcohol in moderation (if at all), eating a balanced diet, embracing regular moderate to high-intensity exercise, engaging with others, and staying up to date with preventive healthcare screenings, among others.

It’s also important that people with a history of depression are aware that their mental health might be putting them at a greater risk of physical ailments. Physical and mental health are often siloed from one another, seen as distinct specialties, Guthrie said. So people have to advocate for themselves, making sure their provider addresses both aspects of their health.

“This dichotomy does not reflect people’s own lived experience, and doctors and other healthcare professionals need to get better at considering people’s problems more holistically,” he said.