Continued cannabis use and risk of incidence and persistence of psychotic symptoms: 10 year follow-up cohort study
BMJ 2011; 342 doi: https://doi.org/10.1136/bmj.d738 (Published 01 March 2011) Cite this as: BMJ 2011;342:d738
All rapid responses
Rapid responses are electronic comments to the editor. They enable our users to debate issues raised in articles published on bmj.com. A rapid response is first posted online. If you need the URL (web address) of an individual response, simply click on the response headline and copy the URL from the browser window. A proportion of responses will, after editing, be published online and in the print journal as letters, which are indexed in PubMed. Rapid responses are not indexed in PubMed and they are not journal articles. The BMJ reserves the right to remove responses which are being wilfully misrepresented as published articles or when it is brought to our attention that a response spreads misinformation.
From March 2022, the word limit for rapid responses will be 600 words not including references and author details. We will no longer post responses that exceed this limit.
The word limit for letters selected from posted responses remains 300 words.
Cannabis is a psychoactive substance. It should be treated with
respect and certainly not used by children. However, all these studies
about psychosis are treated sensationally by the media. The fact is that
cannabis is extremely unlikely to cause anyone any harm and this latest
study confirms that. There is no evidence that cannabis causes psychosis
although it is clearly a risk factor. All the more reason why it is urgent
that we introduce a regulated system of production and supply. Six million
people use cannabis regularly and the current system of prohibition
creates far more harm than cannabis ever has and fails to protect children
or the vulnerable at all.
The sensationalist treatment of this story completely overlooks the
relative harmfulness of cannabis which, in fact, is 100 times safer than
alcohol and 1000 times less toxic. The continuing prohibition of cannabis
is undemocratic, unjust and immensely damaging to our society. A tax and
regulate system would reduce harms, enable the police to concentrate on
real crime and provide a boost to the UK economy of 6 billion per annum.
Competing interests: I am the leader of the Legalise Cannabis Alliance
Of course drug misuse of any kind can lead to mental problems, what
is vital to grasp in this case is that the whole drug experience is
compromised by the legal status of users. The precursors to psychosis are
surely anxiety attacks and paranoia, and these are as much a product of
legal and social context as the person and the drugs themselves. The
opprobrium concerning some drug use has been conditioned into the public
psyche, it is highly oppressive and must feel very similar to that
experienced by minority groups such as gays, who whilst still encountering
prejudice are at least now protected in law (as opposed to being
persecuted by it as they were historically), and as still experienced by
the users of some drugs (prejudice and law). The witchunt continues with
all kinds of tertiary and collateral punishments such as social service
intervention, loss of employment, driving licence revocation, being
excluded - it is hardly surprising people want to keep under the radar and
suffer anxiety.
This is what people must understand about the nature of drug law; it
is a denial of being, a full body removal from civil society to the status
of underclass by merit of simple drug choice. In terms of harm caused it
is a self-fulfilling prophesy both on the physical level (prosecution and
harms caused by lack of consumer protection associated with a criminal
market) and mental (fear of arrest etc, social marginalisation, fear of
seeking help and support even during a crisis).
This as an invasion of inner space by the state. Whilst access to the
mind states is controlled through criminalisation of the markets, those
enterring the supposedly forbidden areas are subject to a psychological
attack as the imposed context changes what might otherwise be divine,
enlightened, magical, harmonious, collective or euphoric mind states into
a neurotic insecurity of self and others.
Competing interests: No competing interests
Re:The key issue for any drug misuse harm, is context
There are plenty of people who regularly smoke cannabis and don't
consider themselves to be an exluded, persecuted underclass. There may,
however, be many people who feel they are part of an underclass who smoke
cannabis.
A notice on my local 'head-shop' door in Bath reads, 'The South-West
- where nice people take drugs' and that typifies the attitude to cannabis
use in this region. It's something that quite normal people do who are not
considered peculiar or anti-social in any way. I have also know totally
normal people in London who smoke cannabis and have good jobs, dress
normally and, if anything, see themselves as being in the higher echelons
of society. I don't think the stereotype of the unemployed 'crustie' or
ageing hippy really represents the majority of cannabis smokers.
Furthermore, if someone having smoked cannabis five times in their
life is classed as a cannabis smoker, then probably a third of the
population under 60 could be classed that way.
Competing interests: No competing interests