HIV POSITIVE  & Nutrition
Medical Marijuana

Use of Marijuana in Neurological and Movement Disorders

1. What research has been done and what is known about the possible medical uses of marijuana?

There have been numerous studies both in animals and in various clinical states on the use of cannabinoids on neurological and various movement disorders. These results range from anecdotal reports to surveys and clinical trials. Marijuana or tetrahydrocannabinol (THC) is reported to have some antispasticity, analgesic, antitremor, and antiataxia actions, as well as some activity in multiple sclerosis (MS) and in spinal cord injury patients.

The spasticity and nocturnal spasms produced by MS and partial spinal cord injury have been reported to be relieved by smoked marijuana and to some extent by oral THC in numerous anecdotal reports. The effect seems to appear rapidly with smoked marijuana; patients are able to titrate the dose by the amount they smoke. No large-scale controlled studies or studies to compare either smoked or oral THC with other available therapies have been reported. Several relatively good therapeutic alternatives exist. There is no published evidence that the cannabinoid drugs are superior or even equivalent.

Substantial experimental animal literature exists showing that various cannabinoids, given primarily by parenteral routes, have a substantial anticonvulsant effect in the control of various models of epilepsy, especially generalized and partial tonic-clonic seizures. Scant information is available about the human experience with the use of marijuana or cannabinoids for the treatment of epilepsy. This is an area of potential value, especially for cannabis therapies by other than the smoked route.

Several single case histories have been reported indicating some benefit of smoked marijuana for dystonic states. It must be remembered that dystonia is a clinical syndrome with numerous potential causes, and the information available now does not differentiate which causes are most likely to be improved. Smoked marijuana and oral THC have been tested in the treatment of Parkinson's disease and Huntington's chorea without success.

The cannabinoids also have been used as experimental immunologic modifiers to treat such conditions as the animal models of experimental allergic encephalomyelitis (EAE) and neuritis. Parenteral cannabinoids have been successful in modifying EAE in animals, suggesting that cannabinoids may be of value in a more fundamental way by altering the root cause of a disease such as MS rather than simply treating its symptoms. Smoked marijuana would not be acceptable for such a role because of the variability of dose with the smoked route.

2. What are the major unanswered scientific questions?

The discovery of dedicated systems of central nervous system (CNS) neurons approximately 8 years ago, which express receptors specific for the cannabinoids, is of major scientific interest and importance. The distribution of these cannabinoid receptor-bearing neurons corresponds well with the clinical effects of smoked marijuana; for instance, their presence in the forebrain may relate to adverse changes in short-term memory, but perhaps positively in the control of epilepsy. Cannabinoid receptors in the brainstem and cerebellum may relate to the recognized incoordination that accompanies smoked marijuana use. The discovery of intrinsic ligands for these receptors in the mammalian brain is also of great importance. This system of cannabinoid receptors and ligands may be analogous to the discovery of opiate receptors and endorphins, which linked various opium derivatives (heroin and morphine) to an intrinsic system of neurons in the CNS. That discovery was of major importance for pain research.

The major unanswered scientific questions are:

  • How useful is smoked marijuana of known specific potency in controlling various neurologic conditions?

  • In comparative studies, how useful is smoked marijuana in altering objective abnormalities such as spasticity versus current standard therapies that have already been approved for human use?

  • Can alternative delivery systems (other than the oral route) be developed to provide rapidity of action with more safety than smoked marijuana?
  • Can available or newly developed synthetic cannabinoids be used more effectively to stimulate or block receptor activity in the cannabinoid system of the CNS?
  • What are the immune-modulating characteristics of the cannabinoids and can they be used for therapeutic human benefit?
  • Can the long-term risks of daily smoked marijuana be quantified so that useful risk versus benefit ratios can be determined, especially when considering treatment of long-term conditions such as spasticity or epilepsy?

3. What are the diseases or conditions for which marijuana might have potential as a treatment and which merit further study?

Marijuana or the use of other cannabinoids as human therapies might be considered for treating spasticity and nocturnal spasms complicating MS and spinal cord injury, for various active epilepsy states, for some forms of dystonia, and perhaps most interestingly, for treating neuropathic pain (Zeltser et al. 1991). (Also see the chapter titled Analgesia.) Neuropathic pain complicates many CNS diseases. Few available therapies provide even partial relief.


Zeltser, R.; Seltzer, Z.; Eisen, A.; Feigenbaum, J.J.; and Mechoulam, R. Suppression of neuropathic pain behavior in rats by a non-psychotropic synthetic cannabinoid with NMDA receptor-blocking properties. Pain 47(1):95-103, October 1991.

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