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Professor Jim Mills on Cannabis

 Cannabis is a controversial substance in twentieth-first century Britain.  Currently a Class B drug for which consumers can be jailed if caught in illegal possession of the substance, it nevertheless remains the most commonly used illegal intoxicant in the UK, with around a third of the population reporting that they have used it at some point in their lives and around 16% of those under the age of twenty-four claiming to have used it in the last year (  Successive governments over the last decade have debated whether to treat the drug more liberally, and in 2008 rejected a more relaxed approach, while experts have differed on the harms associated with consumption.  Meanwhile, medical scientists have been licensed in the UK to work with cannabis to develop legal medicines for the treatment of pain associated with serious conditions like cancer and multiple sclerosis.

The image above is taken from the first government sponsored research into cannabis, which was published not in 1994 but in 1894.  When Britain had an empire it found itself in charge of two of the world's largest cannabis consuming societies in India and Egypt.  In the former the plant readily grows wild and texts from the Hindu religion suggest that communities there had long been aware of its medicinal qualities, its recreational potential, and the harms and side-effects of regular use.  British doctors and officials were less familiar with the substance.  Some were fascinated by its ability to relieve pain and the symptoms of diseases such as cholera and rabies, and recommended its use by Victorian doctors back in Britain.  Others feared that it caused mental illness based on their observations at local psychiatric units, while critics of empire called it 'the most horrible intoxicant the world has yet produced'.

In India the British administration chose to tax the substance, using a similar system to that used in Britain today for tobacco.  As such, when links to mental illness were made and critics pointed to the dangers of using the substance the government had to be seen to act.  The Indian Hemp Drugs Commission (IHDC) was appointed in 1893 to review the medical evidence, and to assess the social and economic impacts of consumption of the drug.  After almost a year of traveling around south Asia the Commission reported.  Eight volumes of evidence were published.  The IHDC concluded that the moderate use of cannabis substances did not cause physical harm, that consumers seemed to find it easier to give up their habit than did alcohol drinkers, but that excessive use did lead to physical damage such as bronchitis, although this came with the caveat that this was the case with all intoxicants.  The conclusions on the mental consequences of using hemp drugs were similarly attached to stipulations about moderate and excessive use. The IHDC declared that ‘the Commission have come to the conclusion that the moderate use of hemp drugs produces no injurious effects on the mind’ but that ‘it appears that the excessive use of hemp drugs may, especially in cases where there is any weakness or hereditary predisposition, induce insanity’.  The Commission was sure that cannabis consumers did not become violent or commit criminal acts because of their use of the substance.

All eight volumes of the report can be found ready-to-read on the website of the National Library of Scotland;  While the Commission did its work over a century ago, its story is still of relevance today.  Since its conclusions were published we have learned more than the commissioners knew about the drug. It has been established which chemicals in the plant act on the human body, and what parts of the human body are affected by the plant.  It turns out that the plant is highly complex and that chemicals contained within it can shape our most basic functions such as mood, sleep, and appetite.  As such there can be significant benefits from using the substance for those suffering serious illness or chronic pain, and limited risks for adults that take small doses on an occasional basis, while at the same time there may be risk of great harm for adolescents on whose maturing bodies cannabis can have permanent impacts.  The complexity of the plant and its myriad effects on human bodies means that there remains disagreement among scientists about the potential and harms of using the drug, dithering by politicians about how to regulate consumption of preparations of the plant, and confusion on the part of consumers and their opponents about the risks and benefits of using cannabis. What the Commission of the 1890s shows us is that it is only by making the effort to review all of the evidence, and being sure to seek balanced conclusions, can well-informed and reliable advice be offered on drugs.


1. Why has cannabis been the subject of such controversy for the British?
2. What does the image suggest about cannabis consumers in nineteenth-century India?  Can you answer this question without seeing the other photographs from the Commission?
3. What were the conclusions of the Indian Hemp Drugs Commission?

Further information
Leslie Iversen's The Science of Marijuana is a readable summary of the topic published in 2007 by the pharmacologist who is now chair of the Advisory Council on the Misuse of Drugs, the Government's main source of information on narcotics and intoxicants.  The author of this page has published a two volume history of cannabis with Oxford University Press, Cannabis Britannica: Empire, trade and prohibition, 1800-1928 (2005) and Cannabis Nation: Control and consumption in Britain, 1928-2008 (2012). 

Professor Jim Mills on Cannabis