The debate around cannabis

Cannabis sativa has long been of interest to psychiatrists for its perceived negative effects on mood and cognition. In India, it is known by various names, including ‘bhang’, ‘ganja’, ‘charas’, and ‘hashish’.

Cannabis sativa has been used for centuries by humans for its effects on the mind. It is mostly smoked, and at times mixed with tobacco. It can be eaten, usually cooked in a cookie or cake. Oily formulations are also available, and these can be imbibed as oils or as capsules. Inhaled cannabis penetrates the brain within seconds, and has abrupt central nervous system (CNS) effects. Eating the product produces a much slower onset of action. Eating cannabis-laden cookies (‘bhang golis’, ‘pakoras’) or drinking them in the form of ‘thandai’ is widely prevalent in India.

The major psychotomimetic agent in Cannabis sativa is delta-9-tetrahydrocannabinol (THC). There is growing interest in another cannabinoid, namely cannabidiol (CBD), which may have antipsychotic, anti-inflammatory and neuroprotective properties.

THC and synthetic cannabinoids are increasingly being used to stimulate appetite in people with HIV-AIDS and cancer. The anti-nausea property of THC is utilised in ameliorating nausea associated with chemotherapy. Cannabinoids are also being used to treat acute and chronic pain syndromes. Nabilone, a synthetic cannabinoid, has been shown to ameliorate chronic neuropathic pain, headache, and fibromyalgia pain. A combination which contains both THC and CBD has been used in the management of pain associated with multiple sclerosis.

An enduring debate is whether THC can lead to addiction and dependence. In humans, whilst a dependence syndrome has been shown, tolerance (taking larger doses of the substance to obtain the same ‘high’) does not necessarily occur for all of its effects. Also, many users do not increase their use once they have reached some sort of plateau. The highly lipophilic nature of THC ensures that it remains in the brain for weeks, and is excreted only slowly upon cessation of heavy regular use. This prevents a rapid and dramatic withdrawal syndrome seen with nicotine or alcohol. Withdrawal effects that have been documented include sleep difficulties, loss of appetite, weight loss, restlessness, irritability, and anger.

Cannabis sativa, however, remains the most widely used illicit drug worldwide. The frequency and potency of cannabis use have exploded globally in the last two decades. Broader global debates about the decriminalisation and legalisation of cannabis continue to take place. This is partly because of the resurgence of interest in cannabis as medicine. Jurisdictions across the globe are legalising the medical use of cannabis, and some are legalising even recreational (non-medical) use. This growing movement has found some clamour in India as well. If India were to ever decriminalise cannabis, policymakers should ensure that it is not commercialised. Enough protections should be in place for children, adolescents, and those with established mental illnesses — groups that are most vulnerable to the detrimental effects of the drug.

(The author is a senior consultant psychiatrist)