Should the use of cannabis be legalised? Assessment statement D.10.3 in the Medicines and Drugs option asks students to discuss the arguments for and against the legalisation of cannabis. The teacher’s notes given alongside the statement are not that helpful and in fact some of the arguments often given are not really specific to cannabis. For example, because cannabis is often imbibed through smoking, arguments about causing damage to the lungs and increased likelihood of cancer etc. are given even though they more accurately refer to nicotine and the products of combustion of tobacco leaf. Similarly the argument that taking cannabis leads on to taking harder drugs is not really about cannabis as such but any illegal drug. There is some sound research that cannabis can give relief for certain diseases which is an argument for legalising it but the counter argument often given is that taking cannabis can lead to mental illness. Opponents of this argument often say that there is no real evidence to support it – perhaps people who already have a mental illness are more likely to be cannabis users, i.e. which triggers which?. A recent study published in the British Medical Journal does now support the argument that taking cannabis does cause psychotic disorders such as schizophrenia.

A group of researchers from Germany, The Netherlands, Switzerland and the U.K. studied a group of 1,923 young people between the ages of 14 and 24. They were carefully screened beforehand to ensure they had no previous diagnosis of psychotic disorders and were initially reported to be non-cannabis users. Over a ten year period they were monitored for both cannabis use and psychotic disorders. The findings showed that taking cannabis significantly increased the risk of developing psychotic disorders. The study did determine that social factors and the taking of other sorts of drugs did not appear to be significant but did not determine whether the stronger types of cannabis (i.e. skunk) caused more disorders than the milder cannabis resin or marijuana.