Management of substance abuse

The health and social effects of nonmedical cannabis use

New WHO publication on cannabis


Cannabis is globally the most commonly used psychoactive substance under international control. In 2013, an estimated 181.8 million people aged 15-64 years used cannabis for nonmedical purposes globally (UNODC, 2015). There is an increasing demand for treatment for cannabis-use disorders and associated health conditions in high- and middle-income countries.

Almost 20 years have passed since the World Health Organization (WHO) published a report on the health consequences of cannabis use. Since then there has been significant research on the effects of cannabis use on health. I am therefore pleased to present this update on the health and social consequences of nonmedical cannabis use, with a special focus on the effects on young people and on long-term frequent use. This report focuses on nonmedical use of cannabis, building on contributions from a broad range of experts and researchers from different parts of the world. It aims to present current knowledge on the impact of nonmedical cannabis use on health, from its impact on brain development to its role in respiratory diseases.

The potential medical utility of cannabis - including the pharmacology, toxicology and possible therapeutic applications of the cannabis plant - is outside the scope of this report.

I hope that Member States, institutions and organizations will be able to make use of this report when prioritizing areas for future international research on the health and social consequences of nonmedical cannabis use.


Dr Shekhar Saxena
Department of Mental Health
and Substance Abuse