The
Pharmaceutical Journal Vol 266 No 7144 p524|
Controversial cannabis |
Controversial cannabisThe emphasis on drugs of misuse in this special issue of The Journal provides an opportunity to examine the way in which measures to prevent a drug's misuse can also hinder its therapeutic use. Cannabis sativa is a case in point, and it is encouraging to see that its potential in diseases such as multiple sclerosis is at last beginning to receive some serious consideration. Since the 1960s cannabis has been classified by international agencies as an addictive drug devoid of any medical value. This is a strange decision in view of the fact that it has been employed for traditional therapeutic purposes for literally thousands of years by many cultures, although at the same time its potential for misuse has been recognised. Unfortunately for those who place their faith in logic, cannabis has found a place in modern societies where the possibility that it might prove useful in certain applications is overridden by what seem to be political considerations. In the 28th century BC, hemp was cultivated for its fibre by the Chinese. Its narcotic properties and misuse as a hallucinogen were recognised later. It was once taken as an infusion in wine. But apparently the Chinese preferred the languor of opium to the ecstasy of hemp. From Central Asia the plant was brought to India where its remarkable intoxicating properties were first appreciated about the 10th century of our era. From there it spread to almost every country of the world, since conditions for its cultivation are not critical. Dioscorides in the first century already knew of it, described the plant, and mentioned it not only as a source of rope but as a remedy for earache and swellings. Galen, a century later, wrote of hemp seed: “There are those who eat it also cooked with other confections in a sort of dessert taken after meals with drinks to excite pleasure. It creates much excitement, and when taken too generously affects the head, emitting a warm vapour and acting as a drug.” Cannabis, as ganja, bhang and marijuana, acquired a religious significance in some cultures. In Africa and the West Indies the Rastafarians ascribed divine virtues to cannabis, and indeed still do. Since there are some 150,000 Rastafarians in Jamaica, to mention only one place, smoking of ganja has been widespread and has spread to other religious groups. The herb is used as a tonic and as a general remedy for many minor complaints. It is given to children to improve their performance at school, and much is consumed in the form of tea rather than smoked. One effect of an official unwillingness to permit cannabis to make a case for itself in the treatment of certain painful conditions has been to create a mystique around it. There is a widespread belief that, contrary to the effects of synthetic cannabinoids based on cannabis, the crude drug contains other compounds that counteract the undesirable effects attributable to a refined preparation. Over the years, political considerations have hindered the serious examination of such ideas. One major motive affecting the attitude of governments to cannabis and its possible legalisation may be that, as with some other drugs of addiction, smuggling and the commerce connected with it brings massive profits for the black marketeers, in which governments have no share, and motives for violence abound. It may be significant that tobacco, alcohol and cannabis are the substances that are most widely abused by children and adolescents. An editorial in Nature for April 5 draws attention to the arguments now being aired in the Supreme Court of the United States over the de facto legalisation of medical uses of cannabis in several states of the union, and the possibility of extending this attitude. Before this discussion many other governments have refused to sanction any medical uses of marijuana, and have even refused to consider its clinical testing for painful conditions where it is reputed to ease the pain and restore the appetite. In the light of all this, it is encouraging to read last week's report of a symposium on cannabis and cannabinoids organised by the Royal Pharmaceutical Society's Academy of Pharmaceutical Sciences (PJ, April 14, p519), which heard about progress with British trials of cannabis and cannabinoids in patients with multiple sclerosis, acute post-operative pain or chronic pain. A step in the right direction, but we are still far from any clear logical position on cannabis, its virtues and vices. The controversy will no doubt continue. |