Chronic pain and mood disorders can often go hand-in-hand. In fact, as many as 50% of people with chronic pain also have depression. It seems that one particular pair of conditions – back pain and depression – may be particularly widespread. Considering how often chronic pain and mood disorders can co-occur, this isn’t very surprising. After all, back pain is one of the most commonly-reported pain conditions, and depression is one of the most common mood disorders.
Both back pain and depression afflict a large number of people.
Over 26 million people in the United States suffer from back pain, making it the leading cause of disability among people in the U.S. under the age of 45. People who have low back pain are commonly in poorer physical and mental health than people without low back pain.
Around 20.9 million people in the United States suffer from some sort of mood disorder. Out of these people, a whopping 14.8 million have depression. Depression can (and often does) co-occur with other mood disorders, as well as with illnesses, pain, and medical conditions.
Back pain and depression often co-occur, largely because it’s possible for each condition to cause (or worsen) the other.
Dealing with chronic back pain can cause a lot of stress. Back pain can even affect a person’s ability to work, interfere with relationships, and chip away at self-esteem. Sleep can be disrupted by back pain, and the ensuing fatigue can further decrease quality of life.
Back pain can also make physical activity difficult or unappealing. Even if, in the long run, physical activity might help with back pain, it can initially be hard to get started or cause some aches and pains. Lessened physical fitness can further reduce self-esteem and interfere with relationships.
Aside from the effects of back pain, the pain itself can increase the risk of depression. It’s easy to focus on pain, which can magnify its effects. The higher the perception of pain is, the more likely it is to cause depression. Once depression has set in, it can cause emotional interpretations of pain, which lead to increased perception of pain. In other words, pain worsens depression, and depression worsens pain, which further worsens pain. As is obvious, the cycle can go around and around, worsening steadily over time if there is no intervention.
Just as back pain can lead to depression, depression can lead to back pain. Sleep disturbance, social withdrawal, difficulty at work, lowered self-esteem, and withdrawal from activities can all occur with depression. Additionally, many people experience physical symptoms, like pain, as a result of depression. Indeed, for some people, physical pain may be the primary symptom of their depression.
Also, some overuse or abuse of some medications can lead to depression. Opioids, for instance, are a pain medication, but they carry a high risk of abuse, addiction, and depression. Unfortunately, when depression is causing or contributing to back pain, treating the back pain is unlikely to work unless paired with treatment for depression. This can lead to feelings of hopelessness about ineffective treatment, which can further exacerbate depression and the risk for overuse of pain medications.
Recent research suggests there may be deeper reasons for the common co-occurrence of back pain and depression.
A study carried out by researchers at UC Irvine and UCLA examined the brains of rodents with chronic pain. They found that chronic pain can cause brain inflammation. This pain-derived brain inflammation causes faster growth and activation of a type of immune cell, called microglia. Microglia cells trigger chemical signals that restrict dopamine release. Dopamine aids in controlling the reward and pleasure centers of the brain, but it’s also involved in pain responses. As noted on Scientific American’s blog, it’s also involved in depressive behavior:
“[D]opamine could also be important in major depressive disorder. People with depression often exhibit reduced motivation, anhedonia (a decrease in pleasure from usually enjoyed things), sometimes motor decreases as well. All of these are linked with dopamine.”
Opioid pain medications also work by triggering the release of dopamine. However, the pain-derived brain inflammation and its resultant increased microglia cells mean that opioids can fail to trigger a dopamine response. This explains why opioids are often ineffective in treating chronic pain. If further research can continue to explain the mechanisms behind the relationship between chronic pain and depression, a targeted, more effective therapy can be developed.
Researchers are also considering the possibility of genetics playing a role. Data concerning over 2,000 twins was analyzed to look for genetic factors relating to both back pain and depression. Interestingly, the group with the strongest association between back pain and depression was the non-identical twin group. When identical pairs of twins were considered, the association disappeared.
According to the study’s authors, this suggests that factors other than genetics likely influence the association between back pain and depression. However, they do note that it is still unclear whether there are genetic factors that predispose individuals to these conditions, and further studies are required to be certain.
Just as the development of back pain and depression can go hand-in-hand, treatment for these conditions can work together, too.
Treating a person’s pain while ignoring his or her depression can prove ineffective, and treating his or her depression while ignoring his or her pain can be ineffective, too. However, just because treating one or the other may not solve both issues completely doesn’t mean it can’t help, as explained at Everyday Health:
“What’s interesting about back pain and depression is that they seem to be so closely tied that getting depression relief may actually lead to back pain relief… On the flip side of the coin, getting back pain relief can also help the depression improve.”
Therefore, treating one or the other is much better than treating neither.
The best case scenario, though, is undergoing treatment for both back pain and depression. The first step in getting treatment is discussing all issues, physical, mental, and emotional, with a primary care physician. From there, the physician should be able to suggest specialists and coordinate treatment for both conditions.
Do you struggle with back pain and depression?
Image by Jenny Williams via Flickr