Extract from Openmind 151, May/ June 2008

Should cannabis be restored to class B? Better spend the money on education about the real risks, reports Katherine Darton.

Cannabis has been an illegal class C drug since January 2004, when it was reclassified from class B. The difference between these two classes is in the penalties for dealing and for possession. For class B these are: for dealing, up to 14 years in prison or an unlimited fine or both; and for possession, up to five years in prison or an unlimited fine or both. For class C the penalty for dealing is the same as for class B, but the penalty for possession is up to two years in prison or an unlimited fine or both. [1]

Since reclassification, there have been many reports in the media, relating psychotic episodes to the use of cannabis, and in particular to skunk, which is generally agreed to be more potent than the strains of the plant from which it was first derived. Because of the anxiety relating cannabis to serious mental health problems, some people believe that cannabis should be restored to class B to reflect the risk of harm that accompanies its use, believing that reclassification has carried with it a message that cannabis is relatively benign. Although its use is perceived by many people to be increasing, figures published in the latest British Crime Survey show that it has declined since 2004. [2]

While many people believe that cannabis strength, as measured by content of tetra-hydrocannabinol (THC, the main active ingredient thought to be responsible for the psychotic effects) has increased markedly since the 1960s and ‘70s, others deny this. But a look at various cannabis websites shows that skunk has been bred specifically to increase the THC content, and different strains are advertised by this, with a clear message that the higher, the stronger, the more desirable. So while some strains are indeed no stronger than they were in 1960, others may be many times more potent in terms of THC content. Moreover, another ingredient of cannabis, cannabidiol (CBD) may have antipsychotic effects, so that if these two ingredients are balanced, as they are in herbal hash or grass, psychotic effects may be much less likely. But skunk contains far more THC than CBD, and so the balance is in favour of psychotic effects. [3]

A recent report in The Lancet stated that there was a 40 per cent increase in risk of psychosis in people studied who had ever used cannabis, with an increased risk of up to 200 per cent in those who used cannabis most heavily. [4] Teenagers and young adults are most susceptible and most need to be warned of possible adverse effects. Apart from the risk of psychosis, a study of the use of cannabis by young women found it was associated with later depression and anxiety. [5] Young people in a group who are using cannabis may be under considerable peer pressure to join in, even after a bad experience has alerted them to their susceptibility.

The general consensus among groups who may be considered most expert in the subject is that reclassification to class B will make little or no difference to cannabis use. Far better, it is suggested, to spend money on education about the real risk of harm. [6] The majority of cannabis users experience no ill effects on their mental health, but, in those who are susceptible, cannabis will trigger a psychotic episode which may be a one-off, but may be the start of experiences that attract a diagnosis of schizophrenia, a career as a user of mental health services, and a struggle to lead a normal happy life. And smoking cannabis is, of course, smoking – and bad for your physical health too.

Mind’s factsheet, Cannabis and mental health, last updated in November 2007, is available at www.mind.org.uk/Information/Factsheets/.

[1] www.homeoffice.gov.uk/drugs/drugs-law/Class-a-b-c/?view=Standard, accessed 4 March 2008.

[2] Advisory Council on the Misuse of Drugs, 2006, Further consideration of the classification of cannabis under the Misuse of Drugs Act 1971, Home Office.

[3] Jackson, C. 2008, ‘Reefer madness?’, Mental Health Today, March, pp 10-12.

[4] Moore, T.H.M, Zammit, S, Lingford-Hughes, A, Barnes, T.R.E, Jones, P.B, Burke, M. and Lewis, G, 2007, ‘Cannabis use and risk of psychotic or affective mental health outcomes: a systematic review’, The Lancet, vol 370, pp 319-328.

[5] Patton G.C, Coffey C, Carlin J.B, Degenhardt L, Lynskey M, and Hall W, 2002, ‘Cannabis use and mental health in young people’, British Medical Journal, vol. 325, pp. 1195-1198.

[6] Jackson, C. 2008, 'Reefer madness?', Mental Health Today, March, pp 10-12.