"Who is right?" asks Leslie L. Iversen, a professor in the Department of Clinical Pharmacology at Imperial College London School of Medicine and founder of Panos Therapeutics Ltd. "Is cannabis a relatively harmless 'soft drug?' Does it have genuine medical uses that cannot be fulfilled by other medicines? Or ... is cannabis in fact an addictive narcotic drug that governments are right to protect the public from?" These questions are posed to the reader in the first chapter of his book The Science of Marijuana.
Although it was first released by Oxford University Press in 2000, The Science of Marijuana is still a knowledgeable and relatively up-to-date work that delves into the history, pharmacology, chemical composition and related compounds, the effects of and the societal attitude to the drug. Dr. Iversen describes himself as "a scientist who works on understanding how drugs act on the brain" and served as a consultant to the House of Lords Committee on cannabis, which declared, in 1998, that marijuana has both good and bad points. (How uncontroversial of them!)
One major, fascinating fact to be exposed early in the book (Chapter 2, "The Pharmacology of THC") is that cannabinoid receptors exist in the brain and that they may be related to the opiate receptors. This would suggest that there might be naturally occurring cannabinoids in the human body. If this is true, then it is obvious that THC, the drug component of marijuana, works by stimulating the endorphins that regulate cannabinoid activity in the brain. However, as Iversen informs us, more research would be needed to establish this.
Iversen next discusses the effects of cannabis on the central nervous system. He describes both the mostly pleasurable, but sometimes frightening experiences that can occur, that marijuana can cause "double consciousness," in which people can actually train themselves to act normally while intoxicated, and the temporary failure of working memory - though the ability to remember previously learned material remains unaffected.
With regard to medical marijuana, Iversen explains that cannabis was long used as a remedy for constipation, gout, malaria, rheumatism and other various pains in Eastern culture, but wasn’t taken seriously for its medicinal capacities by the West until the 1800s. Unfortunately, as doctors soon discovered:
The potency of commercial preparations varied from pharmacist to pharmacist as there was no means of standardizing the preparations for their content of the active drug. What proved to be an effective dose when using material from one supplier would either have no noticeable effects or would produce unpleasant intoxication.
Due to the problems involved with effectively isolating THC and other cannabinoids, getting a standardized cannabis-based medicine that doctors and governments alike would approve remains difficult. Synthetic analogues of THC are not much better as there is just as narrow a window between pain-killing effects and intoxication as with natural THC. Dronabinol (registered as Marinol), which is delta-9-THC but with low abuse potential, and Nabilone (registered as Cesamet), an analogue of THC, are both discussed in terms of helping chemotherapy patients to deal with nausea and AIDS patients to fight wasting syndrome. But it would appear that, despite considerable anecdotal evidence that marijuana helps chemotherapy patients and those with AIDS, multiple sclerosis, and glaucoma, other drugs exist that do not justify the use of cannabis.