Medicinal uses for cannabis: Migraine
A migraine is a severe headache that lasts for hours or days, often accompanied by disturbance of vision and nausea and vomiting. The attacks usually re-occur and can be brought on by stress, certain types of food, bright lights, loud noise and even strong smells. About 20% of the popluation has experienced a migraine attack and women are more likely to experience them. A person's first attack usually happens before age 20, and rarely after age 50.
Drugs can either be used to prevent long-term re-occurance, to cut short attacks, or for pain relief once an attack has started. 10-20% of sufferers get no relief from these drugs and many more get incomplete relief or suffer serious side effects.
Cannabis was highly regarded as a treatment for migraine in the 19th century. Dr J.B. Mattison wrote in 1891 that the treating migraine was the most important use of cannabis. Reviewing his own and earlier physicians' experiences, he concluded that cannabis not only blocks the pain, but prevents attacks. In 1913 William Osler expressed his agreement, saying that cannabis was probably the most satisfactory remedy for migraine. Yet there is little mention of the effect of cannabis on migraine in 20th century medical literature.
Individuals have experimented with cannabis however. They report that smoking a little amount of cannabis just as the early-warning signs of an attack (such as flickering vision) appear will prevent the attack from continuing. This may just be another analgesic effect of cannabis (combined with its anti-nausea effect), or it may be actually affecting the unknown biochemistry of the migraine in some manner.
The effect of cannabis on migraine could be an analgesic or anti-emetic effect - the evidence for these has been discussed elsewhere. There may also be a specific effect on migraines. Migraine attacks may be related to the neurotransmitter serotonin. Certainly, several of the more modern drugs that are currently prescribed to treat migraines work through the mechanism of affecting serotonin.
In 1985 Volfe et al. reported that THC inhibited the release of serotonin from the blood of migraine sufferers during an attack (but not at other times). This could be a clue to future research, which is obviously needed.
Russo (1998) reviewed the usage of cannabis for migraine treatment. The lack of clinical data is unhelpful, but he did conclude that 'cannabis...presents the hypothetical potential for quick, effective, parental treatment of acute migraine', Russo also noted both that many sufferers are not helped adequately by current medications, and that cannabis is a 'far safer alternative' to many currently prescribed anti-migraine drugs.
There is some weak anatomical evidence that cannabis could play some part in migraine treatment. There is a dense concentration of cannabinoid receptors in the periaqueductal gray part of the human brain. Goadsby et al (1991) found that this area of the brain suppresses pain, and is thought to be involved in the creation of a migraine attack.
Goadsby PJ, Gundlach AL. (1991) Localization of [3H]-dihydroergotamine binding sites in the cat central nervous system: Relevance to migraine. Annals of Neurology 29:91-, 94.
Mattison J.B. (1891) Cannabis indica as an anodyne and hypnotic. St Louis Medical Surgical Journal 61: 266
Osler W. (1913) The principles and practice of medicine 8th ed. (New York: Appleton) p1089
E. (1998) Cannabis for Migraine Treatment: The Once and Future Prescription?:
An Historical and Scientific Review. Pain 76
Volfe Z., Dvilansky A. and Nathan I. (1985) Cannabinoids block release of serotonin from platelets induced by plasma from migraine patients. International Journal of Clinical and Pharmacological Research 5: 243-246.