y About 209 million people use cannabis (143) and there are about 24 million people with cannabis use disorders globally (144). While it is estimated that around 1 in 10 cannabis users (and half of daily cannabis users) develop cannabis dependence (145), cannabis use is associated with well documented health risks or harms even for those not meeting criteria for cannabis dependence, including increased risks of negative mental health outcomes (decline in cognitive function, social and educational outcomes, psychosis, mood disorders), physical health (respiratory, cardiovascular diseases, cancer), road traffic accidents and more (146).y Considering high prevalence and well documented health risks associated with cannabis use, wider implementation and scale up of simple advice, brief interventions and, when appropriate, offer of referral to treatment can result in significant health gains at population level.y Use of cannabis or psychostimulants in the recommendation refers to the use of substances without medical prescription. Psychostimulants considered in the recommendations include cocaine and amphetamine-type stimulants.y In ICD-11, hazardous use refers to a pattern of substance use that appreciably increases the risk of harmful (physical or mental) health consequences to the user or to others to an extent that warrants attention and advice from health professionals. The increased risk may be from the frequency of substance use, from the amount used on a given occasion, from risky behaviours associated with substance use or the context of use, from a harmful route of administration, or from a combination of these. The risk may be related to short-term effects of the substance or to longer-term cumulative effects on physical or mental health or functioning. Hazardous drug use has not yet reached the level of having caused harm to physical or mental health of the user or others around the user.y In ICD-11, harmful use refers a pattern of substance use that has caused damage to a person’s physical or mental health or has resulted in behaviour leading to harm to the health of others. The pattern of drug use is evident over a period of at least 12 months if substance use is episodic or at least one month if use is continuous (i.e. daily or almost daily). Harm to the health of the individual occurs due to one or more of the following: (i) behaviour related to intoxication; (ii) direct or secondary toxic effects on body organs and systems; or (iii) a harmful route of administration. Harm to health of others includes any form of physical harm, including trauma or mental disorder that is directly attributable to behaviour related to substance intoxication on the part of the person to whom the diagnosis of harmful pattern of use applies.y Screening refers to asking about drug use with an aim to detect health problems or risks at an early stage before they have caused serious disease or other problems. It includes screening by using standardized instruments but does not refer to testing of biological fluids for the presence of drugs.y The term “brief interventions” refers to a structured, time-limited approach aiming to help individuals reduce or stop substance use. Its intensity and duration ranges from a single short conversation to a few sessions, not necessarily linked to the use of a specific screening instrument.y Brief interventions are often designed to be delivered opportunistically in most settings, including primary care where people may be seeking help for problems unrelated to substance use and which can be delivered by professionals with limited training, thus facilitating access to interventions for a large number of individuals.y Any treatment or support for people using drugs or with drug use disorders should ensure ethical standards – including respect for human rights and the individual’s dignity, and never using humiliating or degrading interventions – in line with the WHO and United Nations Office on Drugs and Crime (UNODC) International standards for the treatmentof drug use disorders (147), as shown in Box 3.1