Comparing cannabis with tobacco

Editor—Henry et al draw attention to the damaging effects of cannabis and the potential problems likely to emerge from its increasing use.¹

There are many aspects to this debate, not least the inevitability of the progress to further use, although other countries have shown this to peak in young people and to deteriorate subsequently. It is also, like most addiction problems, complicated by there being many different side effects, some more serious than others. Like alcohol, cannabis is likely to cause acute physical and psychological as well as long term damage.

Research therefore is urgently required in all these areas. My colleagues and my recent study showed the relation between dose and at least some complications.² It makes intuitive sense that, like other drugs of intoxication, the harmful effects of cannabis are likely to be dose related. The public health message, therefore, becomes like that of illegal drugs—not being geared towards total abstinence so much as minimising the damage and diverting habitual users from the most serious complications.

Cannabis used in small quantities—less than 2 g or 3 g per day—presents quite a different prospect from more heavy use. Truly recreational use (intermittent, infrequent, and non-dependent type use) must present less of a poor prognosis than dependent type use. Patients with dependent type use, similarly to opiate and alcohol use of this sort, are more likely to be unemployed, marginalised, and in the poorer part of the population. In my clinical experience, self medication with cannabis is often a control mechanism for an otherwise unrewarding lifestyle.

Rather than becoming absorbed with the mechanisms for control or the morality of use of the drug, the NHS requires an urgent response to another healthcare imperative, that of providing services for the acute effects of and the chronic damage caused by another largely ignored (by the NHS) addictive drug.