Rates of schizophrenia have not gone up, and it is better for health than high-dose boozing

We have been arguing about cannabis use and its effects for years now, in particular since its more widespread consumption began with the Sixties’ revolutions of style, the youth “counter-culture”, hippie attitudes and sexual liberation.

Research into the effects of cannabis has raised considerable concerns as to the potential health risks, in particular as to whether it can cause or precipitate schizophrenia, and now this latest paper seems to show an association with a modest individuallevel risk of depression and suicidality, but not anxiety.

This is of course a “meta-analysis”, in which the authors have collated findings from 11 other surveys, and they acknowledge that there is no clarity about the doses used by individuals.

Such findings are not uncommon, but not especially helpful. For example, it could be suggested that some users obtained anxiety relief, and as with other proposed health risks it is inherently likely that those with problems/depressive feelings are more likely to seek relief by getting (to use the usual parlance) “stoned”.

The real dilemma with understanding cannabis is that no one really knows who is smoking what. The increasing use of skunk has generated fears of enhancing the risk of psychoses, but the rates for schizophrenia have not gone up over the last 30-40 years.

At present therefore we have a perverse system of criminalising people who prefer cannabis to, say, alcohol, but a government that will not accept medical advice that minimum unit pricing would bring enormous health benefits. No drug is 100 per cent safe, by definition, but the likelihood is that at least a partial switch to, for example, cannabidiol based substances rather than high-dose boozing, would have real health benefits.

Dr Trevor Turner is the former vicepresident of the Royal College of Psychiatrists