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Why are antidepressants used to treat chronic pain?


Woman with back pain
Photo by Karolina Grabowska from Pexels

There are several new strategies today for treating chronic pain.


Chronic pain is non-severe pain that lasts for a long period of time or indefinitely. Examples of chronic pain are fibromyalgia, pain from a back injury, arthritis, a deteriorating hip or knee etc.

The brain produces serotonin which is a “feel good” substance. People suffering from depression have very low levels of serotonin in their bloodstreams. Pain researchers found that people with chronic pain, like fibromyalgia, have low levels of serotonin in their bloodstreams as well. As serotonin circulates in the bloodstream, it is taken up and broken down as a normal process. But antidepressants are made to inhibit or prevent serotonin uptake so that more remains in the bloodstream, and therefore the mood improves.

Researchers found that depressed people who were put on certain antidepressants were reporting improvements in their chronic pain.

So they realized that these medications could also help people suffering from chronic pain who were not necessarily depressed. This has become known as an “off-label use” of medication, which means that the medication is prescribed for something that it was not specifically developed for.

But this whole serotonin mechanism made it clear why so many people with longstanding chronic pain get depressed. The pain depletes their serotonin over time, and they don’t have enough of this natural “feel good” chemical.


There are natural ways of increasing serotonin levels. This is why people who treat chronic pain will also encourage patients to try everything from meditation to positive imagery. They also try to keep them socially connected to friends and family instead of isolating themselves, which can lead to greater depression, making the pain worse.

We do treat cases of chronic pain in dentistry. Most often, it is related to jaw joint problems and the constant low-level pain they can cause. Due to their discomfort, patients with jaw joint problems have a hard time sleeping, which can make the problem worse.


Some antidepressants also work well as sleeping pills. Many of our TMJ (jaw joint) patients go to bed with their mind racing with stressful thoughts. There is even an antidepressant called Elavil that, at a low dose, can reduce the thoughts racing through the patient’s mind at bedtime.

“Off-label use” is something we will hear more about in the future. Of course, the use of medical marijuana is the most prominent example of a substance used for something for which it was not originally intended. There are also new uses for anti-seizure medications for nerve pain. These discoveries and developments will continue to change the way we prescribe some drugs.