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Can cannabis be used to treat osteoarthritis?

Medicinal cannabis has long been recognised as an effective tool for combating the chronic pain associated with osteoarthritis. However, more research is coming to light that suggests the plant could also be used as more than a symptomatic treatment, and actually address the root cause of this debilitating disease.

What is osteoarthritis?

Osteoarthritis is a degenerative joint disease caused by the deterioration of cartilage between joints. Symptoms include painful swelling of the joints, stiffness and reduced range of motion in affected parts of the body.

Osteoarthritis is by far the most common form of arthritis in New Zealand and around the world. In fact, as many as 50 per cent of people over the age of 60 suffer from this disease, according to a report from Best Practice Advocacy Centre New Zealand.

As noted, medicinal cannabis has been proven to help minimise the pain associated with osteoarthritis, but could it also be used to relieve joint inflammation?

How does medical marijuana help treat osteoarthritis?

It’s still too early to definitively say that cannabis could be used to treat osteoarthritis, but the research is promising. A collaborative study from the University of Nottingham, University of Pittsburgh and Virginia Commonwealth University found that JWH133 – a chemical that activates the cannabinoid 2 (CB2) receptor – was effective at treating osteoarthritis in the knees of rats.

The researchers determined this by measuring how the rats distributed their weight across their limbs. The rats that had been injected with JWH133 demonstrated less pain behaviour than those that had been given a placebo.

Does this mean that osteoarthritis sufferers should be smoking cannabis?

Many cannabis advocates are celebrating this study as further evidence of marijuana’s healing powers. While it is possible that the research may encourage further investigation into the use of cannabis as a means of treating osteoarthritis, there were some fairly significant limitations in the study that you should be aware for.

The most obvious is the fact that the study has only been carried out on rats. As the National Health Service explained, this is problematic as it means we don’t know what effects JWH133 could have on humans suffering from osteoarthritis.

Secondly, the rats didn’t actually have true osteoarthritis. Instead, they were injected with monosodium acetate, a chemical that mimics the symptoms of osteoarthritis.

With these limitations in mind, it’s fairly safe to say – at least at this stage – that the role of medicinal cannabis in fighting osteoarthritis will continue to be that of a pain reliever rather than a curative treatment.

Nevertheless, the research is another positive sign for any medical marijuana advocate, and as further research is carried out in the months and years to come, we will undoubtedly gain a better understanding of cannabis’ capacity in osteoarthritis therapy.