Language, law & evidence
In modern medical and public-health language, cannabis preparations containing THC are described as psychoactive drugs or substances. But the cannabis plant is also a source of fibre, seed and other materials, and the political question of whether cannabis should be prohibited is separate from what label we use for it.
The semantic question
The World Health Organization describes cannabis as the most commonly used psychoactive substance under international control and identifies delta-9-tetrahydrocannabinol (THC) as its major psychoactive constituent. In that scientific sense, calling THC-containing cannabis a psychoactive drug is ordinary usage.
WHO 2026 technical briefA cannabis plant can be used to produce psychoactive preparations, medicines, fibre, seed products and cannabinoid extracts. It is therefore useful to distinguish the plant, particular plant parts, THC-containing preparations, isolated cannabinoids and finished products rather than treating every item derived from cannabis as pharmacologically identical.
Home Office cannabis & cannabinoids factsheetCurrent UK law
Home Office guidance summarises the statutory definition as the cannabis plant or any part of it, subject to limited exceptions including the mature stalk, fibre produced from the mature stalk, and seed.
Home Office factsheetTHC and a number of other controlled cannabinoids are Class B drugs in their own right. This is distinct from the legal definition that separately controls cannabis plant material.
Cannabinoid control statusThe Home Office states that pure isolated CBD is not controlled under the Misuse of Drugs Act 1971. However, a CBD product may still be controlled if it contains controlled cannabinoids unless a relevant exemption or other lawful route applies.
CBD legal guidanceHealth evidence
Low overdose toxicity suggests that cannabis has no meaningful health risks.
Public-health sources describe fatal overdose caused solely by cannabis as unlikely. But consuming too much can still worsen severe anxiety, confusion, paranoia, vomiting and other reactions, and impairment can contribute to injuries.
CDC cannabis FAQNHS guidance identifies potential risks including psychosis and dependence, with greater concern as THC content increases in a minority of consumers. Illicit products also create uncertainty about strength, ingredients and quality.
NHS medical cannabisModern scientific sources describe THC as psychoactive and intoxicating. Cannabis can affect memory, attention, coordination, decision-making and reaction time, particulary in novice consumers. Relgious or ritual use often involves large doses of high-THC content cannabis.
WHO cannabis overviewPharmacology
Historical CCGUIDE material
The following pages are retained as historical advocacy and testimony. Their age and context should be kept in mind when comparing them with current medical evidence.
CCGUIDE campaign perspective
Whether we call cannabis a drug, herb, medicine, intoxicant or controlled substance does not by itself answer the question of what the criminal law ought to do.
CCGUIDE continues to argue that adult cannabis possession and cultivation should not attract criminal punishment and that cannabis supply should be addressed through legal reform rather than prohibition alone.
That argument does not require denying that THC is psychoactive, that cannabis can impair people, or that some users develop dependence. Those are evidence questions. Proportionality, regulation and criminalisation are policy questions.
Decriminalisation or legalisation?Parliamentary, legal and campaign sources on cannabis-law reform.
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