Can Depression Make You Sick?

Depression is more than just the psychological symptoms. Your mental health can also affect your physical health, potentially causing pain and illness.

If you have depression, you may have already experienced mysterious physical symptoms. Maybe you get frequent stomachaches or have back pain that won’t go away, but you can’t figure out why.

The reason could well be related to your depression.

While depression may more often be associated with emotional and psychological symptoms, it can also have a big impact on your physical health.

In fact, depression, pain, and physical illness are all closely related. Depression can cause pain and aches, lead to various stomach and heart problems, and make you sick.

Here’s everything you need to know about how and why depression can affect physical health and which symptoms may be related to your mental state.

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The link between depression and physical health

Researchers have been exploring the relationship between depression and physical health for decades.

Scientific and anecdotal evidence indicates that depression can have a profound impact on physical health, showing up as both illness and pain (chronic or sporadic).

In other words, depression and mental health can make you sick and cause physical pain.

The authors of a 2016 research review looked at the prevalence of unexplained painful physical symptoms in depression. They found that people with all types of depression — and particularly those with major depressive disorder (MDD) — frequently report physical symptoms. In fact, about two-thirds of people with MDD experience physical pain.

The review authors also noted that people with more severe psychological symptoms tended to experience higher pain intensity.

Depression can also cause illness, affecting everything from your immune system to your heart to your stomach.

What’s behind the link between depression and physical health?

There are a few theories about the association between depression and physical health, including these hypotheses related to shared neural pathways and brain chemistry:

• Shared pathways in the brain: Depression and chronic pain share certain neural pathways, including in the prefrontal cortex (a part of your brain that helps regulate emotions and pain). This means that when these neural pathways aren’t functioning correctly, both depression and pain may occur.

• Increased protein levels: People with depression may have higher levels of pro-inflammatory cytokines (a group of proteins involved in immunity and inflammation), which may increase pain perception, cause chronic pain and inflammation, and affect immune function.

• Increased neuropeptide levels: People with depression may have elevated levels of a neuropeptide called substance P (a chemical messenger that transmits pain signals to the brain). As a result, they may have increased pain perception.

• Decreased neurotransmitter levels: People with depression have low levels of neurotransmitters such as serotonin and norepinephrine (chemical messengers that influence mood). These same neurotransmitters are involved in pain regulation, and when they don’t function correctly, pain perception may be increased.

Regardless of the exact mechanism, mental health and physical health are linked.

What’s more, the relationship is bidirectional, meaning each can amplify the other. Depression can worsen physical health, and poorer physical health can worsen depression.

What are physical symptoms of depression?

Some of the common physical effects of depression are:

• body aches
• heart problems
• stomach problems
• sleep problems
• immunity problems

This list is by no means exhaustive. If you find yourself experiencing other physical symptoms, they may well be related to depression too.

Here’s a look at how depression can affect physical health and how symptoms may show up.

Body aches

Body aches and pains are among the more common physical symptoms of depression.

People with depression may experience muscle aches and joint pain in certain areas of the body or as a general aching throughout the whole body.

In fact, these symptoms are so common that they’re included in multiple depression severity rating scales (tools to help healthcare professionals diagnose the presence and severity of depression).

The Hamilton Depression Rating Scale, for example, includes:

• backache
• neck ache
• shoulder ache
• headache
• limb pain

In a 2017 study, researchers looked at low back pain and depression in university students and found that depression was a risk factor for developing back pain. Inversely, they also found that back pain increased the risk of developing depressive symptoms.

The authors note that their findings are in line with existing research that suggests people with depression are around 60% more likely to develop back pain in their life.

As we saw above, evidence indicates that depression is associated with changes in pain processing and pain perception, which may be related to body ache symptoms.

Heart problems

Research has shown that depression may increase the risk of developing heart problems over time.

The results of a small 2016 study suggest that people with depression are two to three times more likely to develop heart disease over a 6-year period. The study also reports that more severe depressive symptoms are associated with higher risk levels.

Additionally, depression may increase the risk of high blood pressure (hypertension), one of the main risk factors for various heart conditions.

A small 2013 study involving people who were receiving treatment for high blood pressure found a correlation between unmanaged high blood pressure and depression. These results suggest that depression is a risk factor for high blood pressure and may interfere with blood pressure regulation.

The association between depression and heart problems may be related to depression’s impact on physiological factors (dysregulation of the autonomic system and of inflammation response in the immune system) and lifestyle factors (smoking, alcohol use, diet, and physical activity).

Of course, there are many other risk factors for heart problems, and having depression doesn’t automatically mean you’ll develop heart disease. But it’s important to pay attention to physical symptoms and report them to your doctor.

Stomach problems

Depression and mental health can make you sick, in part because your brain and your stomach are connected.

The two influence each other through a network of pathways called the gut-brain axis.

This connection is partly explained by gut microbiota (sometimes called the gut microbiome or gut flora) — the population of microorganisms that live in your gut and play a crucial role in overall health. These microorganisms include bacteria, viruses, and fungi.

A 2020 study found that certain strains of microbiota were predictive of depression, including strains that play a role in the metabolism (breakdown) of neurotransmitters involved in depression, such as GABA.

These strains created a particular microbiota composition that wasn’t significantly influenced by variables such as diet and smoking. In fact, the compositions were so distinctive that the researchers could correctly diagnose depression in study participants just by examining their microbiota.

The study also suggests that the levels of certain microbiota may influence the imbalance in inflammation that can occur in depression. This could connect the gut-brain axis to the heightened pain perception that people with depression may experience.

Since the gut-brain axis goes both ways, your brain also affects your gut: Your emotions can influence your stomach and intestines.

This means depression can make you physically ill, leading to gastrointestinal and esophageal symptoms such as:

• stomachache
• nausea
• diarrhea
• constipation
• acid reflux
• heartburn
• loss of appetite
• dry mouth

There may also be a link between depression and irritable bowel syndrome.

Sleep problems

Sleep problems are another common physical symptom of depression.

More than 90% of people with depression experience sleep problems, some of which may be due to disruption and dysregulation of sleep-wake cycles (circadian rhythms) and deep sleep (REM sleep).

Research indicates that the relationship between sleep and depression is bidirectional — each influences the other.

Scientists are still trying to figure out how and why the two are related. The authors of a 2019 review suggest that depression and sleep problems may have shared neural pathways. In other words, when certain neurotransmitters aren’t functioning correctly, both sleep problems and depression can happen.

The review authors also report that long-term research has found that insomnia is a risk factor for developing depression or experiencing a relapse of depression. Since the relationship is bidirectional, the opposite is also true: Depression and other mental health conditions can predict insomnia.

For people with depression, sleep problems can show up as:

• insomnia
• difficulty falling asleep
• difficulty staying asleep
• waking too early
• poor sleep quality
• fewer total hours of sleep
• daytime drowsiness
• fatigue
• exhaustion
• lethargy

Additionally, depression often occurs at the same time as diagnosable sleep disorders that make it even harder to get a good night’s rest, including:

• insomnia
• narcolepsy
• sleep apnea and other sleep-disordered breathing
• restless legs syndrome

Sleep loss and lack of quality sleep can also worsen other psychological and physical symptoms of depression and affect your immune system.

Immunity problems

Depression can affect your immunity and may be associated with a weakened immune system.

Researchers are still exploring the relationship between depression and impaired immune system function, but it’s thought that the association may be partly related to pro-inflammatory cytokines and white blood cells.

People with depression may have higher levels of pro-inflammatory cytokines, which can cause an overactive immune response and inflammation, potentially weakening the immune system and increasing the severity of depressive symptoms.

Additionally, people with depression may have lower counts of white blood cells involved in fighting off infection, such as lymphocytes, which can result in immune system dysfunction and a weakened immune response.

When your immune system doesn’t function correctly, you’re at higher risk of infection and illness. Plus, if you do get sick, your body will have a harder time fighting off the illness and getting better.

The takeaway

For many people, depression affects more than just emotional health — it can also affect physical health.

It’s important to pay attention to your body and tell a healthcare professional about any new or worsening symptoms, both emotional and physical. Consider informing all the doctors you see, not just a mental health professional.

Depression is a wide-ranging condition that can call for a wide-ranging medical team. The more information your care team has about your overall health, the better prepared they will be to get to the bottom of any problems and help you treat both the cause and the symptoms.