Most adults use cannabis recreationally without significant adverse effects to their health. In a thirty year career in mental health services, and close working with young adults who used cannabis, I did not encounter any conclusive evidence that cannabis causes psychosis. However, emerging evidence would seem to support the hypothesis that links cannabis with psychosis in a small cohort; in the same manner that a minority of people cannot tolerate gluten, or whose pancreas no longer adequately regulates blood glucose levels. And of course, those who smoke cannabis, either mixed with tobacco or through a pipe, run the same risk of cancer and lung damage as cigarette smokers.
What has been established beyond question is that there is a correlation between cannabis use and psychosis, although this is exceptionally complex. Often, those cannabis users who present with psychosis are poly drug users; their cannabis use is concomitant with the use of of cocaine, ecstasy, LSD, magic mushrooms, Novel Psychedelic Substances (legal highs), alcohol etc. Additionally, there is frequent co-morbidity in the cohort of cannabis users who present with psychosis, i.e. there may have been an underlying, pre-existing health condition, developmental disability, etc.
What has been largely disproven is that cannabis acts as a ‘gateway drug’ in the sense that users begin with a comparatively benign substance like cannabis, but go on to use harder drugs in search of a greater ‘kick.’ The effects of cannabis are highly specific. Users report that it enhances mood and sensory perception, and that music sounds more exciting and vital, visual senses are enhanced etc. This is a million miles away from the effects of, for example heroin, that blunts the emotions.
Neither is it true that street level sellers introduce young persons to cannabis to get them ‘hooked’ before encouraging them to try ‘harder’ drugs. It is true that most alcoholics who now down a bottle or two of vodka per day started with beer, but that is associated with the individual emotional and psychological profile of the addict. When have you ever gone into a off-licence to buy a bottle of wine where the salesperson tries to push you gin instead, because it has a greater ‘kick’? Most street level cannabis dealers are smokers themselves, and deal to friends. What is true though, is that the illegal status of cannabis makes it more likely that those same youngsters come into contact with other, harder drugs, due to the illicit methods and venues involved in obtaining cannabis.
The other main objection to legalisation is that it will increase the availability of cannabis and encourage more people to begin using, increasing the burden placed on the police, NHS, and other agencies. The flaw in this argument is that those burdens already exist. The most cursory visit to any high school in the country, any football ground, or park or recreation ground, will confirm that cannabis use amongst young persons is already at a significant level.
The experience of Portugal, where the experiment of legalising drugs has gone further than any other European state, demonstrates that drug use does not increase following legalisation. On the contrary, an open, regulated and comparatively safe trade in drugs leads to fewer deaths per capita.
Full legalisation will not entirely eliminate the illicit trade. Contraband tobacco is still smuggled into the U.K. despite being entirely legal. But it does go a very significant way to reducing all round risk, eliminates a potential criminal record and addresses drug use as it should, and as it needs, to be addressed- as a health and social rather than a criminal justice issue.
I include a link on the Portuguese model, and a link from the Royal College of Psychiatrists: you will note the the RCPsych link is careful to use language like “might,” “risk” and ”associated” rather than “proven” and ”causes.” There are also a number of useful articles published by The Lancet.
Information for young people about cannabis and how it might affect your mental health.
www.rcpsych.ac.uk
transformdrugs.org