Key Details
The WHO publication, The Health and Social Effects of Nonmedical Cannabis Use, updates its 2016 assessment with research available through 2025. It focuses on health and social harms—not the therapeutic benefits of medically supervised cannabis.
Globally, an estimated 250 million people aged 15–64, or 4.8% of that population, used cannabis in 2024. Use has increased since 2016, while products containing higher concentrations of the psychoactive compound THC have become more widely available.
Risk area | WHO’s updated assessment |
|---|---|
Dependence | An estimated 12% of young people who have ever used cannabis develop dependence; the estimate rises to 33% among at-least-weekly users |
Adolescent development | Regular, heavy use is consistently associated with cognitive impairment, poorer school performance and early school-leaving |
Psychotic disorders | Evidence has strengthened that cannabis can interact with other risk factors to precipitate psychosis; more frequent and potent use carries greater risk |
Pregnancy | Cannabis use is associated with higher likelihood of low birth weight, preterm birth and babies being small for gestational age |
Physical health | Regular smoking is linked to chronic bronchitis and recurrent vomiting; evidence of myocardial infarction and stroke risk is increasing |
Road safety | Driving while intoxicated modestly increases traffic-injury risk, although attributing individual crashes remains difficult |
Adolescents and Frequent Users Face Greater Risks
WHO identifies age, frequency and product potency as important risk factors. Young people commonly initiate cannabis use during their mid-teens, when regular use may interfere with learning and educational attainment.
Heavy adolescent use has been associated with poorer cognitive and psychosocial outcomes. The report cautions that not every association is necessarily causal because family, genetic, environmental and behavioural factors can influence both cannabis use and later outcomes.
Evidence is stronger for cannabis dependence and psychosis. The likelihood of dependence rises substantially with weekly use, while continued use among people with an existing psychotic disorder is associated with more frequent relapses and a poorer course of illness.
Higher-Potency Products Change the Risk Environment
The average concentration of tetrahydrocannabinol (THC) has increased in illicit markets. Jurisdictions permitting commercial sales have also seen products such as concentrated extracts, vaping oils, edibles and beverages.
High doses of THC can produce anxiety, paranoid thoughts, hallucinations and impaired behaviour. Legal markets in some countries have recorded increased emergency-department visits, including incidents involving children who consumed cannabis edibles believing them to be ordinary sweets.
WHO does not conclude that every legalisation model produces identical outcomes. It notes that adverse-event increases have been particularly marked where nonmedical cannabis has been commercialised.
Pregnancy and Physical Health Evidence Is Expanding
A meta-analysis covering more than 21 million pregnancies found cannabis use associated with increased likelihood of:
low birth weight;
preterm birth;
infants being small for gestational age; and
potentially higher perinatal mortality, although evidence for the last outcome was less certain.
For adults, long-term cannabis smoking is associated with cough, sputum, wheezing and chronic bronchitis. Current research does not consistently show that it causes chronic obstructive pulmonary disease.
Evidence connecting frequent use with heart attacks and strokes is strengthening, but WHO calls for larger and better-designed studies. Similarly, evidence remains insufficient to determine whether cannabis independently increases most cancer risks, partly because cannabis and tobacco are frequently used together.
This Is an Evidence Review, Not a Policy Recommendation
The technical brief expressly states that it is not a normative document and does not recommend a particular legal or regulatory model. It also does not provide an India-specific prevalence estimate or assessment of Indian cannabis policy.
Its contribution is narrower: it updates the evidence that governments can use when designing prevention, surveillance, treatment and public-information measures.
What Does “Nonmedical Cannabis Use” Mean?
WHO defines nonmedical cannabis use” as self-administered cannabis use that is neither for a medical purpose nor undertaken under a physician’s supervision according to a specified treatment regimen.
THC is the principal compound responsible for cannabis intoxication. Cannabidiol (CBD) does not produce the same intoxicating effect. Product type, THC concentration, dose and frequency can therefore result in substantially different risk levels.
Policy Relevance
India’s surveillance needs greater detail. National and state-level data should distinguish occasional from regular use and capture age of initiation, product type, potency where measurable, and treatment demand.
Adolescent prevention should reflect differential risk. Public communication can focus on frequent and high-potency use, cognitive effects and psychosis without suggesting that every instance of use produces the same outcome.
Health services need integrated screening. Addiction, mental-health, emergency and maternal-health services should be equipped to identify cannabis use disorders, intoxication, recurrent vomiting and pregnancy-related exposure.
Road-safety systems require better measurement. Toxicological testing, clinical protocols and crash data must distinguish evidence of recent cannabis use from proof of driving impairment.
Policy debate should separate medical access from nonmedical use. The therapeutic value of specific cannabis-derived medicines does not remove the public-health risks associated with unsupervised or high-frequency consumption.
Follow the Full Report Here: The Health and Social Effects of Nonmedical Cannabis Use