Most of what most people see and hear about cannabis and mental health has nothing to do with evidence. Mostly it’s about fear, prejudice and propaganda. Increasingly, the pernicious “drug support” industry is trying to exploit cannabis users as a new source of income.

Yesterday, Rupert Wolfe-Murray, who describes himself as “Editor at Castle Craig rehab clinic” posted an article on Huffpost UK entitled “Can Cannabis Drive You Crazy?”

Given Rupert’s employment it’s no surprise that his answer to his question is a resounding “Yes!”.  I can almost hear him licking his lips and salivating gently as he flicks through the thick wad of notes in his wallet.

Take a look at the Castle Craig rehab clinic’s website.  It is constructed precisely to exploit financially the UK government’s drug strategy.  It uses exactly the right phrases and terminology to check all the government’s tick boxes.  I can imagine James Brokenshire was beside himself with joy at such “on message” propaganda.

The “drug support” industry is one of the most wicked and corrupting influences in modern society.  Entirely for its own benefit it invents quasi-medical conditions and conspires with the police, the CPS and the courts to drum up business for itself.

As with all such “drug support” businesses, Castle Craig lumps all drugs together as one.  The most severe effects of opiate addiction are written about in the same context as cannabis.   Funnily enough though, the most dangerous, harmful and addictive drug of all – alcohol, is treated differently and given its own section.

Certainly addiction to opiates is an illness that requires medical treatment.  Some users of cocaine, particularly crack, also need healthcare interventions but the vast majority of users of psychedelics, MDMA (Ecstasy) and cannabis experience no ill effects at all.

The myth of cannabis addiction is what Rupert and his cronies in the “drug support” industry make most of their money from.  Little Johnny gets busted with a bit of weed and his solicitor advances his “addiction” in mitigation.  Consequently the court builds up a false statistical base which appears to “prove” there is a problem with cannabis addiction and gifts public money to drug support charlatans to “treat” the “problem”.  This self-perpetuating and corrupt cycle generates oodles of cash for Rupert and his co-conspirators.

An important caveat is that Castle Craig may well offer excellent and much needed services for those addicted to drugs such as alcohol and heroin.  That is a noble cause.  What is wrong are the false pretences of cannabis “addiction” and “psychosis” in order to obtain public money by deception.   After alcohol, cannabis is the biggest market of all and that is what the drug support industry seeks to exploit.

Jason Reed also posted a rebuttal of Rupert’s article here.

The scientific evidence about “cannabis addiction” is that the prevalence, rate (about 9% among users) and withdrawal symptoms associated with cannabis dependency are similar to or less serious than for caffeine dependence. (Hall et al 2001, Coffey et al 2002, Copeland et al 2004, DSM-IV)

The scientific evidence about cannabis and mental health is:

1. Hickman et al, 2009. A review of all published research so, by definition­, not cherry picked. It shows that the risk of lifetime cannabis use correlatin­g with a single diagnosis of psychosis is at worst 0.013% and probably less than 0.003%.

2. Hospital Episode Statistics. Count of finished admission episodes (FAE) with a primary diagnosis of mental and behavioural disorders due to use of cannabinoids (ICD10 code F12) and alcohol (ICD10 code F10)

Cannabinoids (F12)

2009-10 713
2010-11 799

Alcohol (F10)

2009-10 47,402
2010-11 47,287

Source: Hospital Episode Statistics (HES), The NHS Information Centre for health and social care.

There are three million regular users of cannabis (Atha et al 2011) and 31 million regular users of alcohol (NHS Information Centre 2009). Therefore alcohol use is six times more likely to result in admission for mental and behavioural disorders.

3. Frisher et al 2009. The ACMD commissioned a study by Keele University into the trends in schizophrenia specifically to test the claims in the media of a link between it and cannabis. It looked at almost 600,000 patients and concluded that “..the incidence and prevalence of schizophrenia and psychoses were either stable or declining” despite alleged increased use of allegedly more potent cannabis.