Scientists have discovered what links chronic pain and depression, which may lead to new and more effective treatments for depression symptoms.
Acute pain is something that we feel only for short periods. It's what tells us that we may have gotten injured. Chronic pain, however, is a pain that can last for three months or more. Injury or illness may cause chronic pain, but sometimes, the cause may be unclear.
People who have chronic pain often also experience depression and mood disorders. This may not be surprising, as chronic pain can impact a person's day to day life. Thus, chronic pain can be as much a physical condition as it is an emotional one. Depression, stress, anxiety, and other similar conditions can also interfere with the body's ability to produce natural painkillers.
While it seems logical that chronic pain and depression often go hand in hand, scientists have found how exactly this occurs. A new study claims that chronic pain can make genetic changes in regions of the brain related to depression and anxiety. These findings may aid in the development of new treatments that specifically target the link between chronic pain and depression.
The research team studied mice that exhibited pain symptoms similar to those of chronic pain in humans. For this study, the researchers studied pain in mice for 10 weeks. Previous mouse pain studies had only lasted for a week or so.
Initially, the researchers noticed that the mice were only exhibiting symptoms of pain. After some weeks, though, the mice began exhibiting symptoms of depression and anxiety as well.
When the researchers noticed this, they examined gene activity in the nucleus accumbens, the medial prefrontal cortex, and the periaqueductal gray of the mice's brains. These three regions have links to depression and anxiety in mice. The researchers found that 40 genes in these three regions had a significantly different level of activity compared to the same genes in mice that weren't exhibiting pain symptoms.
These same genes are also present in human brains. Scientists have already identified the connection between these genes and depression in humans. According to the findings, some of the affected genes are linked to inflammation. Scientists have previously associated inflammation in the brain with the development of depression. Thus, these particular genes may be the reason why chronic pain can give rise to depression symptoms.
Thus, the link between chronic pain and depression is seated deep in the brain itself. It's not just a simple causality, wherein experiencing chronic pain as well as its impact on everyday life is obviously depressing and stressful. Understanding the deeper link between chronic pain and depression can lead to better medication.
For now, chronic pain sufferers are given anti-depressants as treatment. However, these meds can take a long time to take effect. The findings of the study can help develop better treatment for the condition, one that can specifically target the genes in question.
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