It has become an indelible etching on the national psyche; cannabis and psychosis dovetail like fish and chips. The impact of cannabis on the mind has been well documented in the British press, but it remains an unfortunate muddle as the link is as far from clear as one is led to believe.
In a recently published time series analysis, The Effect of Reclassification of cannabis on hospital admissions for cannabis psychosis, the relationship between laws and mental health have been assessed with the data analysed from 1999 through 2010. The Gordon Brown Labour government used the emerging concerns of cannabis related psychosis as ardent justification to reclassify cannabis from Class C to a stricter Class B. This move was firmly against the ACMD's advice and gave rise to the now infamous incident that saw Professor David Nutt, the then Chair of the ACMD, lose his position. It's also noteworthy that a similar situation has occurred in recent weeks with the arbitrary banning of Khat; once again this decision was made by the Home Secretary without the backing of the ACMD's advice or evidence.
Cannabis was downgraded to Class C in 2004 under Tony Blair, it was then put back to Class B in 2009. So what can we learn from the psychosis related hospital admissions during this time? Logic would tell us that an appropriate impact would have been made, but surprisingly, cannabis psychosis actually fell when it was Class C, and had no impact when it was in Class B. On one hand, this is widely in keeping with the projections made by those in criminology and science, but the reduction under Class C was unexpected. The new findings quickly went viral. Alex Stevens, Professor of Criminal Justice at the University of Kent, said:
"Told you so - that the move up to Class B would not reduce psychosis." But Professor Stevens was: "Surprised that it was followed by a reduction."
The debate around harsher laws and how it relates to purposed reductions in substance harms has raged for some time. The complex relationship of drug harms from a socio-economic view vs. a pharmacological standpoint is an area in much need of a discussion, it should be free from emotional investment, and based on hard empirical evidence: there is no evidence to support the logic underpinning the 2009 move to Class B.
Relationships between our daily lives and mental health is clearly as complex as the very essence of life itself. Professor Robin Murray has worked in the field of cannabis and mental health and is quite clear that he has changed his mind on the issue of schizophrenia on many occasions. He also points out the ingrained complexity of environmental factors. For example, you are 6 times more likely to suffer psychotic episodes if you're a migrant, and the increase risk to mental health is far greater if you live in a city, and the risk increases to the size of the city you live in. What this can tell us is that set and setting are paramount to our mental well-being, so it's not a big leap to explore the possibilities of how law enforcement and classifications of substances affects the mental health of their users. A paper by Dr. Richard Bunce also delves into this realm: Social and Political Sources of Drug Effects: The Case of Bad Trips on Psychedelics.
For many years, there has been the necessitous disclaimer of correlation is not causation and this needs firm reiteration whenever we teeter on the wire of substance harms and their pharmacology. In a recent talk for Reason TV, Neuropsychopharmacologist, Dr Carl Hart, made the eminent case for evidence over perception. Using the example of Crystal Meth, he found that the harms that society projects often don't live up to the pharmacological realities; popular myths and folklore on drug harms are ever circular, and as a result education is the true casualty.
Fellow Neuropsychopharmacologist, Professor David Nutt, has written what is perhaps the definitive book on drug education: Drugs Without the Hot Air. This must have book for parents and teachers gives a non-excluding summary on the evidence of drug harms. Professor Nutt's previous work within the ACMD showed that to stop one case of cannabis related psychosis we need to prevent 5000 young men from using the substance, and 7000 young women. The risk remains statistically very low, but of course worthy of concern.
The hyperbolic version of events would lead us to believe that just one cannabis joint can irreparably damage the brain. The Daily Mail has actually won awards for the misinterpretation of drug science and their willful projection of myth. A rather brilliant analysis of the somewhat infamous "Just ONE cannabis joint 'can bring on schizophrenia' as well as damaging memory" can be found on the Neurobonkers site. A catastrophic amount of errors were found in the Daily Mail's report, and with a rather lethargic, begrudging correction subsequently following. Consequently, The Daily Mail won the Orwellian Prize for Journalistic Misrepresentation, a prize founded by Oxford University Neuroscientist, Professor Dorothy Bishop.
We need to ask ourselves: does the risk of cannabis related psychosis give us enough reason to arrest and punish by law? Professor David Nutt goes on to say in his book: a prisoner is 10 times more likely than the general population to commit suicide, and around 40% of men and 60% of women will have some form of neurotic disorder. It's quite apparent that our drug laws are not making much sense, and they certainly don't correspond to the nuanced subject of mental health. Our drug laws are designed to protect society from potential harms but are actually predicating just as many by placing them under the control of law enforcement and punishment. The debate needs to be had on how best to minimise all harms of all drugs. If the law and socio-economic factors are playing a part in those harms, then we need to appropriately address and reform as we're mandated to do. What we don't need is a bolstering of political rhetoric; we must allow the evidence to lead our policy makers.