Cannabis & Chronic Pain: How Research Has Evolved to Show Promising Treatment Effects

Cannabis sativa, and its active ingredient tetrahydrocannabinol (THC), has been used to treat pain for thousands of years. In fact, the first evidence of humans cultivating the plant for pain relief dates all the way back to 3,000 BC.

Fast-forward to today and cannabis – and its medicinal qualities – is still very much in play. Clinical trials have become an important way to learn more about the potential of cannabis and how the drug can help people with illnesses such as chronic pain. The research suggests cannabis may be worth a shot, considering 100 million Americans currently experience chronic pain, and treatment options are often limited and bring with them unwanted side effects.

How Does Cannabis Help Treat Pain?

A major clinical trial by McGill University in Montreal broke ground in 2010, finding that three puffs of cannabis a day helps to relieve chronic nerve pain. The study showed that cannabis does indeed relieve pain, by “changing the way the nerves function,” according to lead researcher Mark Ware, MD. Researchers examined patients suffering from chronic pain as the result of surgery or injury, who were given different doses of cannabis lasting five days. Each day, participants were asked to take a single puff three times.

The drug can activate neurons in the nervous system, producing therapeutic effects on areas of the brain that control pleasure and memory, for example. “We’ve shown again that cannabis is analgesic,” Ware said, referring to pain-killing capabilities. “Clearly, it has medical value.”

To understand exactly how cannabis reduces pain, let's take a closer look the plant’s best-known ingredient: tetrahydrocannabinol, or THC.

Is More THC Better for Pain?

McGill University researchers tested three different potencies of cannabis. THC concentrations were 2.5, 6, and 9.4 percent. Each person was given all four strengths – and placebos – at random over the course of two months.

Participants were then asked to rate their pain on a scale of zero to 10 at the end of each test, 10 being the worst. Results showed that people who used cannabis at the highest potency experienced lower pain intensity, better moods, and improved sleep quality. These participants reduced their pain to 5.4 on the scale, while those on the placebo were at 6.1.

This suggests that higher levels of THC are more likely to make a difference. Although this difference may be marginal, and is not enough to replace existing pain relief treatments, said Ware, “any reduction in pain is important.” Using cannabis for pain reduction could help offset the use of controversial opioid painkillers, as well.

What This Means for Patients

At the time of the McGill study, about 10-15 percent of chronic pain clinic patients were using cannabis for pain control. Since then, cannabis has repeatedly shown to reduce pain, among other medicinal benefits. McGill University is just one of many institutes that continue research, most recently finding it to be a risk-free alternative for long-term pain management. Now, medical cannabis is used by well over 2 million Americans.

Potency has also evolved significantly over time. While the highest used in Ware’s study was 9.4 percent, he noted at the time that cannabis “on the street” contained concentrations higher than 10 percent. Recent studies, though, have seen values as much as 30 percent, implying that patients have developed a tolerance for higher doses of THC.

In the end, the effects of cannabis vary from patient to patient, and some find particular species more beneficial than others. It’s important to take time investigating different strains, their THC levels, and other important factors to find a fit that works. Researchers all agree that cannabis removes pain; just how much is dependent on the patient.

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