The higher-than-average prevalence of mental illnesses among those with chronic pain has been recognized for years. However, it’s only recently that studies have given some clues as to why people with chronic pain are so likely to suffer from mental illnesses.

Living with chronic pain is a challenge in itself.

The everyday logistics of living with chronic pain can quickly become complicated. Sometimes getting a good night’s sleep is difficult, because a painful hip or back can interfere with sleep. The activities involved in getting ready for the day, such as buttoning up a shirt or bending to put on socks, can be problematic. Facing a day of work or interactions with loved ones can be daunting while in pain and fatigued from a poor night’s sleep.

Chronic pain can cause frustration, anger, and a host of other emotions, so it’s really not too surprising that mental illnesses, particularly mood disorders, are so common among people with chronic pain. According to Harvard Health Publications:

“Pain, especially chronic pain, is an emotional condition as well as a physical sensation. It is a complex experience that affects thought, mood, and behavior and can lead to isolation, immobility, and drug dependence… People with chronic pain have three times the average risk of developing psychiatric symptoms — usually mood or anxiety disorders.”

Additionally, in a study published by Arthritis & Rheumatism, it was found that no less than one-sixth of people with chronic widespread pain also suffered from a mental disorder. In this study, testing scores indicated that participants with chronic pain but without a diagnosed mental disorder were still very distressed and at risk of developing a mental disorder. The study concluded that physicians treating individual’s with chronic widespread pain should be on the lookout for warning signs of mental disorders, such as anxiety disorders or clinical depression.

The Department of Veteran Affairs published findings concerning the relationship between post-traumatic stress disorder (PTSD) and chronic pain. These findings suggested that PTSD and chronic pain frequently go hand in hand. It was also pointed out that several mechanisms, such as fear, avoidance, anxiety, sensitivity, and catastrophizing, occur in both PTSD and chronic pain, and that these mechanisms can encourage the ongoing nature of the conditions.

Other causes of chronic pain and mental changes were brought to light in a recent study conducted in the United Kingdom.

This study, which was published by the Warwick Medical School, found that many pain patients struggle with their relationships with their bodies. In other words, they have trouble seeing themselves as “the real me” anymore. Chronic pain sufferers are also very uncertain of their futures and are highly aware of the pain-related restrictions of their bodies.

Additionally, the study found that people with chronic pain frequently feel lost in the healthcare system, as though no one will be able to alleviate their pain. Chronic pain sufferers might also worry about “proving” their pain, as though acting like they’re “too sick” or “not sick enough” will affect their credibility. This worry among chronic pain sufferers that they might not be believed could discourage them from speaking to a physician about painful symptoms, which could lead to mental distress or worsen existing mental illnesses.

Despite the obvious correlations between chronic pain and mental changes, it’s still unclear exactly how the conditions interact together.

As pointed out in an article on GoodTherapy.org, “Correlation is not causation.” This means that simply because chronic pain and mental changes frequently co-occur, it doesn’t mean that one condition necessarily causes the other.

Constant pain can grate on the emotions and exacerbate mental illnesses. At the same time, mental illnesses place stress on the body and can exacerbate physical pain. Since each condition can feed the other, no one is quite sure which is cause and which is effect. Indeed, it’s even unclear if one causes the other at all; it’s possible that the two occur independently of each other and then interact.

A study with mice might shed some light on the relationship between chronic pain and mental changes.

A study conducted by researchers at Stanford University School of Medicine found that chronic pain can affect motivation. The idea that chronic pain could rob someone of their motivation to engage in life is not a new one, but this study showed just how profoundly chronic pain can impact motivation levels. In the study, mice with chronic pain showed a decreased willingness to work for food less than a week after the pain began. Even when the pain was relieved with medications, mice who had previously experienced chronic pain were less willing to work for their food.

Further study focused on the nucleus accumbens in the mice, which is responsible for dictating motivation. It was suggested that interactions between the nucleus accumbens and a protein called galanin could be responsible for the lowered motivation. Like mice, humans have a nucleus accumbens. Therefore, if this research is continued and deepened, it might someday be possible to manipulate the interactions between the nucleus accumbens and galanin protein to restore chronic pain sufferers’ previous levels of motivation.

Another recent study found differences in the way people’s brains worked when they had chronic pain.

Researchers at Northwestern University observed the active areas of the brain during a task using a functional MRI. It was found that in pain-free individuals, when one region of the brain is active, the other regions are inactive. This state of mental equilibrium didn’t happen in people with chronic pain. Instead one area, a front region of the cortex usually associated with emotions, didn’t quiet down when it should have. This particular region of the brain was “stuck on full throttle,” which could eventually alter connections between neurons.

The researchers in this study suggested that, because the constant pain causes some areas of the brain to remain continuously active, the “wiring” of the brain can be changed. These changes could potentially be responsible for mental changes associated with chronic pain, such as decision-making ability or mood.

It’s possible that these pain-related disturbances caused in the brain could be responsible for mental illnesses in chronic pain patients. If this is the case, it makes it more imperative that individuals with chronic pain pursue treatment. Additionally, it can be hoped that if the mechanisms behind pain-related mental illnesses can be better understood, these conditions can be more effectively treated.

Has your chronic pain ever contributed to a mental disorder or changes in mood?

Image by julien haler via Flickr

GET FREE EMAIL UPDATES!

Weekly updates on conditions, treatments, and news about everything happening inside pain medicine.

You have Successfully Subscribed!