Cannabis may be used to ease the painful muscle stiffness caused by multiple sclerosis (MS), according to scientists in the UK.

They studied adult MS patients from 22 different specialist centres across the country.

The patients were split into two groups: one group was given cannabis extract (tetrahydrocannabinol) and the other a dummy pill every for 12-weeks.

The treatments were given in gradually increasing doses from 2.5mg up to a maximum of 25mg for two weeks, followed by maintenance doses for the remaining 10 weeks. The aim was to see if cannabis extract alleviated or improved muscle stiffness, associated pain, muscle spasms, and sleep quality, using a validated 11-point rating scale.

At the end of the study, the relief from muscle stiffness was twice as high among the cannabis extract group in comparison with the placebo group. Muscle stiffness was alleviated in just under 30% of those given cannabis compared with just under 16% of those treated with the placebo.

The differences were most noticeable among patients not already using antispasmodic treatment, among whom almost 40% of those taking the cannabis extract gained relief compared with just over 16% of those taking placebo.

Side effects were higher among those taking the cannabis extract and highest during the first two weeks of treatment. Nervous system disorders and gut problems were the most commonly reported side effects, but none was severe.

Up to 90% of MS patients endure painful muscle stiffness at some point during the course of their disease, which reduces their mobility and interferes with daily routine activities and sleep quality. But current treatments often fail to resolve symptoms fully, and can be harmful.

As a result, many MS patients have experimented with alternative therapies, including cannabis.

According to the researchers, the results of their study indicate that cannabis extract could be a useful treatment for the muscle problems typical of MS, and could also provide effective pain relief, particularly for those in considerable pain.

The study was published in the Journal of Neurology Neurosurgery and Psychiatry.