The first chapter in this section (Chapter 12) summarises the results of the analysis of the health effects of cannabis that have been presented in the preceding chapters. It also compares the health and psychological effects of cannabis with those of alcohol and tobacco. Our purpose in making these comparisons is to minimise the double standards that have sometimes been used in appraising the health effects of cannabis.

Our comparison of health effects is not intended to be an implicit argument for cannabis legalisation, as some critics have claimed any such comparison is (e.g. Ghodse, 1996). Proponents of cannabis law reform have used as one of their arguments the assertion that cannabis use produces fewer adverse health effects than alcohol and tobacco (e.g. Zimmer and Morgan, 1997). Statements of fact do not have straightforward implications for policy, as Hume observed over 200 years ago. There is a compelling argument to be made in the opposite direction, namely, given the adverse public health impact of alcohol and tobacco use in Western societies, we should be very cautious about encouraging the widespread use of a recreational drug that may combine some of the adverse health effects of alcohol with those of tobacco smoking (e.g. Drummond, 2002).

The benefits of cannabis use - the subject of Chapter 13 - are more controversial still. Proponents of current policy are reluctant to discuss the possibility that cannabis use may have any benefits. Proponents of reform have, with few exceptions, also been softly spoken on the benefits of recreational cannabis use apart from the potential use of cannabis and cannabinoids to treat symptoms of chronic illnesses that are unresponsive to current medical treatment. We briefly discuss the empirical evidence on the therapeutic uses of cannabis. We discuss the policy debate about ‘medical marijuana’ in an appendix because, as we argue in more detail there, the ‘medical marijuana’ debate is a marginal issue in the larger policy debate about the legal status of recreational cannabis use. As this chapter makes clear, there has been very little research on the benefits of recreational cannabis use. We have included a chapter on the topic because we believe that the benefits of recreational use should be explicitly discussed when debating societal policies towards cannabis use.