An estimated 350,000 people in the United States are living with multiple sclerosis (MS), a debilitating and sometimes fatal disorder of the central nervous system. MS is the most common debilitating neurologic disease of young people, often appearing between the ages of 20 and 40, affecting more women than men. Symptoms vary considerably from person to person; however, one frequently noted concomitant is spasticity, which causes pain, spasms, loss of function and difficulties in nursing care.

MS exacerbations appear to be caused by abnormal immune activity that causes inflammation and the destruction of myelin (the protective covering of nerve fibers) in the brain or spinal cord. MS most frequently presents at onset as a relapsing and remitting disorder, where symptoms come and go. Current treatment of MS is primarily symptomatic, focusing on such problems as spasticity, pain, fatigue, bladder problems and depression.

Anecdotal reports and a small controlled study have reported that cannabis improved spasticity and, to some extent, improved tremor in MS patients. Many studies of the pharmacology of cannabis have identified effects on motor systems of the central nervous system that have the potential of affecting tremor and spasticity. A recent carefully controlled study of the efficacy of THC in experimental allergic encephalomyelitis, the animal model of MS, demonstrated significant amelioration of these two MS symptoms. Moreover, cannabis has demonstrated effects on immune function that also have the potential of reducing the autoimmune attack that is thought to be the underlying pathogenic process in MS.

Many MS patients report that cannabis has a startling and profound effect on muscle spasms, tremors, balance, bladder control, speech and eyesight. Many wheelchair-bound patients report that they can walk unaided when they have smoked cannabis.

A House of Lords reports states that the British Multiple Sclerosis Society (consisting of some 35,000 MS-suffering patients) estimates that as many as 4% of their population already use cannabis for the relief of their symptoms despite the considerable legal risks associated with prohibition. The chairman of the committee went on to state that, "We have seen enough evidence to convince us that a doctor might legitimately want to prescribe cannabis to relieve...the symptoms of multiple sclerosis and that the criminal law ought not to stand in the way." Many of the witnesses for that report shared the British Medical Association's view that "A high priority should be given to carefully controlled trials of cannabinoids in patients with chronic spastic disorders." The BMA has requested that the synthetic cannabinoids Nabilone and Dronabinol be officially licensed for use in MS and other spastic disorders.

Research findings on cannabis and MS

Numerous case studies, surveys and double-blind studies have reported improvement in patients treated with cannabinoids for symptoms including spasticity, chronic pain, tremor, sexual dysfunction, bowel and bladder dysfunctions, vision dimness, dysfunctions of walking and balance (ataxia), and memory loss.(12-20) Cannabinoids have been shown in animal models to measurably lessen MS symptoms and may also halt the progression of the disease.(21)

A recent British survey of MS patients found that 43 percent of respondents used cannabis therapeutically. Among them, nearly three quarters said that cannabis mitigated their spasms, and more than half said it alleviated their pain. A survey published in August 2003 in the Canadian Journal of Neurological Sciences reported that 96 percent of Canadian MS patients believe that cannabis is therapeutically useful for treating the disease. Of those who admitted using cannabis medicinally, the majority found it to be beneficial, particularly in the treatment of chronic pain, spasticity and depression. (22) The accompanying editorial states, "This is an exciting time for cannabinoid research. There is a growing amount of data to suggest that cannabis (marijuana) can alleviate symptoms like muscle spasticity and pain in patients with MS." (23)

The published results of a GW Pharmaceuticals Phase II study showed that pain relief was significantly superior to placebo and there were subjective improvements in spasm frequency, bladder control, spasticity and sleep. (24) Subsequent Phase III trials have shown positive results including statistically significant reductions in neuropathic pain, spasticity and sleep disturbance. These results are currently awaiting publication.

A U.K. study published recently in the journal Lancet looked at 630 multiple sclerosis patients after 15 weeks of orally delivered treatment. Fifty-seven percent of the patients taking a whole cannabis extract said their pain had eased, compared with 50 percent who took capsules containing THC and 37 percent who were given placebo capsules. Patients also reported improved sleep and fewer or less intense muscle spasms and stiffness. Those who could walk were significantly more mobile as measured by a walking test. The investigators also noted there were fewer relapses in the treatment groups; however, the study was not designed to investigate impact on relapses. (25) An accompanying editorial points out that current data supporting the benefit of cannabinoid treatment of spasticity in MS is now as strong as for any available pharmaceutical agent. (26)

The distribution of cannabinoid receptors in the brain suggests that they may play a role in movement control. Only recently have researchers found an animal model for MS, called experimental allergic encephalomyelitits (EAE), allowing testing for symptom suppression. Recent pre-clinical reports found that cannabinoids lessened both tremor and spasticity in mice suffering from EAE.(27)

In addition to studying the potential role of marijuana and its derivatives in the treatment of MS-related symptoms, scientists are exploring the potential of cannabinoids to inhibit neurodegeneration. A 2003 study that the American MS Society calls "interesting and potentially exciting" demonstrated that cannabinoids were able to slow the disease process in mice by offering neuroprotection against EAE.(28). After analyzing the findings, authors at London's Institute of Neurology concluded, "In addition to symptom management, cannabis may also slow down the neurodegenerative processes that ultimately lead to chronic disability in multiple sclerosis and probably other diseases."(29)