Since the Constitutional Court's ruling last year relating to private personal consumption of cannabis, there has been increased interest in the potential health implications of using the plant. Few healthcare professionals have, however, explored how the compounds within cannabis affect the human body.
"Cannabis has been used by humans for centuries for various neuropsychiatric conditions including pain and seizure disorders. By the late 19th and early 20th centuries, cannabis-containing medicines were commonly used by physicians for indications similar to the effects for which the plant is being investigated today," says Dr Louis Roos, a psychiatrist practising at Akeso Arcadia, part of the Akeso network of psychiatric hospitals offering treatment for addiction disorders and mental health concerns.
"During the 20th century, scientific study of cannabis was limited due to its illegal status in many countries, however recent decades have seen major breakthroughs in our understanding of the drug. While research into potential medicinal effects is still in its infancy, we are starting to understand how it interacts with the brain and may influence certain mental and physiological processes," he says.
"The question may be asked, 'on a scale of one to ten, how dangerous is cannabis?' however, there is unfortunately no simple answer, as there are many complex factors and finer nuances to be considered."
"There is still a blind belief by many members of the public that cannabis could be a cure-all treatment for various conditions with no harmful effects, however the evidence simply does not support this. Cannabis contains more than 500 active components and, while it is possible that some may have medicinal potential, we are only in the very early stages of developing an understanding of the ratios and concentrations of these compounds that could have either positive or negative outcomes for various conditions.
"Nonetheless, I would encourage healthcare professionals to acquaint themselves with the available research in order to cultivate a better informed, more nuanced understanding of cannabis, even though doctors cannot yet prescribe cannabis as treatment for any condition."
Dr Roos points out that for any cannabis-containing product to be sold or marketed as medicine in this country, it would first need to go through a lengthy process to be registered with the South African Health Products Regulatory Authority. While certain products have been registered with the relevant health authorities in other countries, at this stage no cannabis products are registered for use in South Africa.
Cannabis has been labelled as a "gateway drug" with evidence that it primes the brain for a heightened response to other drugs, however Dr Roos points out that this also holds true for both alcohol and nicotine.
"Adolescents in particular should not use cannabis, as there is a much higher risk of addiction in younger people.
"Approximately nine percent of cannabis users become dependent on the drug, however the dependency rate tends to be higher among people who start using cannabis at a younger age. To put this in context, a lifetime risk of dependence is as high as 15% for alcohol and 32% for nicotine users."
Health risks of smoking cannabis
"There are potential health risks to using cannabis that people should be aware of. People may be tempted to experiment with cannabis based on a common, though incorrect, perception that it is safe for everyone. The available scientific information suggests there are potential risks that warrant careful consideration.
"Using cannabis regularly can have detrimental effects on the stability of a multitude of psychiatric disorders, including mood disorders, such as depression and bipolar disorder, anxiety and psychotic disorders."
Significant evidence suggests a link between schizophrenia and cannabis use, however a causal link has not been definitively established. It has been suggested that cannabis use may act as a trigger for schizophrenia in predisposed individuals, thereby resulting in earlier age of onset of schizophrenia.
He adds that long-term heavy use of cannabis is associated with amotivational syndrome, which is described as a sense of apathy, poor concentration and a lack of motivation for work, social and other activities. "However this syndrome is probably, at least in some part, more likely due to the effects of chronic intoxication," he says.
It should be noted that cannabis intoxication significantly impairs driving ability. Dr Roos warns that the risk of being involved in a car accident is doubled soon after a driver uses cannabis. The risk is compounded when alcohol and cannabis are used together.
Long-term cannabis smoking has been associated with the development of lung cancer and testicular cancer, however Dr Roos points out that there is weak evidence to suggest a direct causal link. It should also be noted that smoking cannabis over the long-term may predispose individuals to chronic airway conditions and may increase the risk for certain vascular conditions.
He explains that the endocannabinoid system, which is a system of cannabinoid receptors in the body and central nervous system, is involved in multiple processes of brain development. "As THC, which is the component that creates the feeling of intoxication associated with cannabis, is far more potent than the endocannabinoids that are naturally produced in the body, using cannabis while the brain is still developing could potentially have detrimental consequences.
"Brain development continues into the mid-20s, and this is one of the reasons that it is strongly advised that younger people, as well as pregnant or breastfeeding women, avoid using cannabis. There is, however, no good evidence to suggest at what age cannabis use may become less harmful," he adds.
"There have been media reports of children using synthetic cannabinoids commonly known as 'spice', which are much more potent than even the strongest cannabis. These compounds can lead to severe intoxication, serious health risks such as inducing psychosis, and have a very high addictive potential," Dr Roos notes.
Preclinical evidence suggests that CBD, which is a component of cannabis that does not contribute to the cannabis "high" as THC does, could potentially prove helpful for multiple anxiety disorders, including post-traumatic stress disorder (PTSD), generalised anxiety disorder, panic disorder, obsessive compulsive disorder and social anxiety disorder. More research is needed on the effects in individuals with existing anxiety disorders and long-term efficacy has yet to be established.
Several small studies in humans with psychosis, which is defined as a mental state in which an individual loses touch with reality and may experience delusions or hallucinations, have reported CBD could potentially offer some benefit for reducing psychotic symptoms, however more extensive and rigorous studies are needed before any solid conclusions can be reached.
The effectiveness of medical cannabis as a treatment for epilepsy remains in question, and the mechanisms involved are little understood. In some countries, however, a CBD-containing drug manufactured by a British company has been registered for Dravet syndrome, which is characterised by intractable seizures in children.
"It has been hypothesized that an interplay between anti-seizure activity and anti-inflammatory properties of cannabis could account for the effectiveness observed in some patients. Studies in animals show CBD to have anticonvulsant properties, however in certain individuals THC, which is the compound responsible for the 'high' feeling, can trigger seizures," Dr Roos adds.
Certain symptoms of multiple sclerosis, a neurological disease, may be improved through cannabis use. "Muscle spasticity, spasms, neuropathic pain and bladder dysfunction may be alleviated, while some patients also report improvement in fatigue and reduction in sleep disturbance and dysesthesia, which is discomfort associated with nerve damage," he explains.
"In some other countries, but not in South Africa, a type of medication known as Nabiximols prepared from cannabis extracts THC and CBD has received regulatory approval and may be prescribed for pain and spasticity.
"Cannabis shows considerable promise as an area for development in medicine, however there are also serious concerns, especially in those with pre-existing psychiatric disorders and those at risk, younger individuals and pregnant women, that must be acknowledged.
"The boom of home-growers who sell whole cannabis, edibles and extracts and promote them as a cure-all for a variety of conditions is of concern as this industry is unregulated and illegal, as the law currently stands. While cannabis isn't all bad and is not without potential medical benefit, from a medical perspective, this is deeply troubling and the public should be warned that there are potential risks to using cannabis," Dr Roos concluded.
Roos, J. (2017) Cannabinoid use in neuropsychiatric conditions: An introduction to cannabinoids, the endocannabinoid system and potential therapeutic applications. NEURON SA, Volume 10 No 3 Issue 34 2017
References are available on request
The endocannabinoid system
The study of cannabis and its active components led to the discovery of the endocannabinoid system as recently as the early 1990s, and much of this complicated system remains to be discovered. Even though there have been massive gains in our knowledge of the workings of the endocannabinoid system, most medical practitioners have a very limited, if any, knowledge of this system.
The endocannabinoid system involves a system of cannabinoid receptors in the central nervous system and throughout the body that regulates appetite, pain sensation, mood and memory, among other processes.
Cannabinoids are a group of chemical compounds that 'plug in' to the endocannabinoid system. There are three different types, namely endocannabinoids, which are produced in the body naturally; phytocannabinoids, which are derived from the cannabis plant; and synthetic cannabinoids, which are artificially manufactured.
THC is the main psychoactive cannabinoid and is responsible for the "high" for which recreational users use cannabis. The effects of THC include reduced coordination, decreased muscle spasticity, changes in mood and cognition, increased appetite, pain reduction, and stimulation of the brain's reward circuitry.
CBD is a non-psychoactive constituent of cannabis, therefore it does not give rise to intoxication. CBD has been shown to have a protective effect on cells of the central nervous system and facilitates production of these cells. Preclinical studies have indicated that CBD has a range of potentially useful effects associated with relief of pain, nausea and anxiety, as well as anti-inflammatory, anti-psychotic and anti-epileptic effects.
The 'entourage effect'
It is believed that the various components of cannabis, including cannabinoids, terpenes and flavonoids, interact and can help to moderate the potentially adverse effects of the main psychoactive components of cannabis. The entourage effect is often used to explain why compounds based on THC alone are not well tolerated or may not have the full beneficial effects of whole cannabis.
About the Akeso Group
Akeso is a group of private in-patient psychiatric hospitals, and is part of the Netcare Group. Akeso provides individual, integrated and family-oriented treatment in specialised in-patient treatment facilities, for a range of psychiatric, psychological and addictive conditions. Please visit www.akeso.co.za, email firstname.lastname@example.org, or contact us on 011 301 0369 for further information. In the event of a psychological crisis, please call 0861 435 787 for assistance. Contact Akeso Arcadia on 087 098 0459.
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