Cannabis is consumed in many different forms, including dried flower for smoking, vaporised extracts, oils, capsules, edible products and medically formulated preparations. While each route of administration carries its own risk profile, the greatest body of evidence linking cannabis to adverse mental health outcomes relates to the regular smoking of high-potency cannabis, particularly among adolescents and young adults whose brains are still developing.
The scientific evidence shows that cannabis carries risks. Frequent or heavy use during adolescence is associated with an increased likelihood of anxiety disorders, psychotic symptoms and, in susceptible individuals, schizophrenia. The risk varies across users. An individual who experiments occasionally faces a different level of risk from someone who consumes cannabis heavily over prolonged periods. Individuals with a personal or family history of schizophrenia, psychosis or certain anxiety disorders appear more vulnerable, with cannabis potentially triggering or worsening underlying conditions.
It is also important to understand the context of the evidence. Many of the mental health studies most frequently cited are based on patients admitted to psychiatric hospitals or substance treatment facilities, representing high-risk clinical populations rather than the estimated 3.5-million to 4-million South African adults who use cannabis. These patients frequently present with multiple risk factors, including pre-existing mental illness, genetic susceptibility and the concurrent use of alcohol, methamphetamine, cocaine, opioids and other substances. Such studies are essential for identifying vulnerable groups and informing public health policy.
For example, in a psychiatric cohort of 500 patients, 68% would represent about 340 individuals. While this is highly significant for understanding risk factors in that specific hospital population, it should not be interpreted as meaning that 68% of all cannabis users or about 2.4-million South Africans face the same level of risk. Clinical cohorts are designed to identify associations in vulnerable populations, not to estimate the prevalence of psychiatric illness among the general adult cannabis-using population.
The health department has recently launched a campaign highlighting the mental health risks associated with cannabis use. This is an important public health message and one that the cannabis industry should support. Cannabis carries real risks, and for some individuals, particularly adolescents, young adults and those with a personal or family history of psychotic illness or severe anxiety, those risks are significant.
The health department has recently launched a campaign highlighting the mental health risks associated with cannabis use. This is an important public health message and one that the cannabis industry should support.
The scientific evidence is strongest for regular, prolonged use of high-potency cannabis during adolescence, when the brain is still developing. Research has associated this pattern of use with an increased risk of anxiety disorders, psychotic symptoms and, in susceptible individuals, schizophrenia. These risks are not evenly distributed across the population. An adult who occasionally consumes cannabis faces a different level of risk from a young person who uses high-potency cannabis daily over an extended period.
Recognising these risks strengthens the case for sensible regulation that includes age restrictions, accurate product labelling, health warnings, quality standards and public education. Good regulation neither minimises the risks nor exaggerates them. Its purpose is to ensure that adults can make informed choices while providing the strongest possible protection for young people and other vulnerable groups.
The bottom line
Cannabis use carries recognised risks. For some individuals, particularly adolescents, young adults, and those with a genetic predisposition to psychosis, schizophrenia or certain anxiety disorders, regular heavy cannabis use may contribute to adverse mental health outcomes. These risks are real and should be communicated honestly through education, product labelling and responsible public health messaging.
Yet, perspective remains essential. South Africa has a population of about 63-million people, with an estimated 3.5-million to 4-million adults using cannabis each year, about 7%-8% of the adult population. Most of these consumers do not present to psychiatric hospitals.
The Constitutional Court recognised that adult private use of cannabis is protected under the constitutional right to privacy. Cannabis should therefore be regulated according to evidence rather than ideology. International evidence consistently shows that cannabis presents a lower risk of fatal overdose, physical dependence and societal harm than alcohol, though it is not without its own health risks, particularly for vulnerable individuals.
The absence of a regulated commercial framework has left consumers exposed to untested products, unknown potency, contaminants and an illicit supply chain that offers no age verification, no quality standards and no meaningful consumer protection. This regulatory vacuum undermines public health and responsible adult access.
A mature cannabis policyshould achieve two objectives simultaneously: protect young people and vulnerable individuals through honest health warnings, education, age restrictions and appropriate labelling, while establishing a lawful, traceable and quality-controlled market that replaces the current informal supply chain.
Good regulation manages the known risks responsibly while recognising that public policy should be proportionate to the evidence and consistent with South Africa’s constitutional and legal framework.
• Botha is a legal strategist, cannabis policy specialist and co-founder of H3 Legal Solutions. He has briefed parliament on cannabis policy and industrialisation matters in South Africa.
