Research has shown that 9% of individuals who experiment with cannabis will become addicted to it. This number increases to 1 in 6 when use starts during adolescence. So it’s with concern that the South African Society of Psychiatrists (SASOP) responds to the recent legalisation of cannabis for personal use. There seems to be a growing public perception of cannabis as a ‘harmless’ plant, and that few measures have been instituted to address this.

And it’s most harmful to the youth. Human brain development and maturation is a process that is guided by the body’s endogenous cannabinoid system and occurs until the early 20’s. Exposure to phyto-cannabinoids (cannabinoids obtained from the cannabis plant) during this vulnerable period may disrupt the process of brain maturation and affect aspects of memory, attention, processing speed and overall intelligence. Cannabis use during the adolescent period may cause lasting cognitive deficits, even after sustained abstinence.

The Global Burden of Diseases Study of 2010 estimates that 2 million years lived with disability were attributed to cannabis. The South African Community Epidemiology Network on Drug Use (SACENDU) reports that, during the 2nd half of 2016, cannabis was the most common primary substance of abuse for persons younger than 20 years presenting to treatment facilities in all areas across South Africa, except for the Free State, Northern Cape and North West.

 A review article by the World Health Organization in 2016 concluded that current evidence points to a modest contributory causal role for cannabis in schizophrenia and that a consistent dose-response relationship exists between cannabis use in adolescence and the risk of developing psychotic symptoms or schizophrenia.

Any change to the legislation regulating cannabis use should have been undertaken in consultation with all the relevant stakeholders, be based on good quality scientific evidence and take into consideration the availability and accessibility of current drug addiction prevention and treatment resources in South Africa. 

SASOP concurs with the Executive Committee of the Central Drug Authority (CDA) of South Africa that the approaches to combat the use and abuse of psychoactive substances should include harm reduction (interventions aimed at reducing the harmful consequences associated with substance use), supply reduction and demand reduction/preventative strategies. We agree with the Executive Committee of the CDA that there is currently insufficient evidence to predict the long-term consequences of the legalization of cannabis. 

The ease of accessing an intoxicating substance may have an underestimated impact on the initiation, frequency and amount of use, and the subsequent risk of developing a substance use disorder. Legalization should therefore not have been considered at this point.

The decriminalisation of cannabis removes the criminal penalty related to the use of cannabis; it allows for a distinction between a drug dealer and an individual experimenting with or addicted to a drug. While SASOP supports the human rights of all individuals, we argue that a decision to protect those addicted to substances should not be viewed as a simple binary decision based on criminal penalties.

In 2001 Portugal augmented the decriminalization of illicit substances with drug dissuasion commissions, increased the number of facilities offering detoxification and therapeutic admissions, increased the number of drug education campaigns and refocused policing efforts on large scale trafficking operations. The decriminalization of cannabis must be preceded by and augmented with similar socially responsible strategies for it to be successful in South Africa. 

In terms of the strong positive public opinion and anecdotal reports favouring medicinal cannabis, no available evidence supports these claims. The exceptions are the moderate quality evidence of medicinal cannabis for treating chronic pain, spasticity due to Multiple Sclerosis and weight loss associated with HIV. This evidence includes trials investigating pharmaceutical medications based on phyto-cannibinoids. Good quality evidence does however exist regarding the frequently occurring side effects of cannabis such as confusion, dizziness, diarrhea, euphoria, fatigue and hallucinations.

 Any potential benefit obtained from cannabis must therefore be weighed against its risk of causing addiction, psychosis, cognitive impairments and a 2.6 times greater likelihood of motor vehicle accidents. SASOP further notes with concern the growing evidence linking cannabis use with an increased risk of an acute myocardial infarction as well as an ischaemic stroke. 

We commend the Medical Control Council’s decision to limit the use of cannabis for medicinal purposes to registered prescribers and for individuals in which an acceptable justification is provided. We support ongoing research on the use of cannabis for medicinal purposes to ensure that its purported and potential benefits can be scientifically measured against medical and societal risks.

Dr Abdul Kader Domingo is a member of the South African Society of Psychiatrists (SASOP) Special Interest Group on Addictions

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