- Substance abuse refers to the harmful or hazardous use of psychoactive substances, including alcohol and illicit drugs.
- At least 15.3 million persons globally have drug-use disorders.
- Injecting drug use is reported in 148 countries, of which 120 report HIV infection among this population.
- It is estimated that in 2008, 155 to 250 million people, or 3.5% to 5.7% of the world's population aged 15-64, used other psychoactive substances, such as cannabis, amphetamines, cocaine, opioids, and non-prescribed psychoactive prescription medication.
- Globally, cannabis is the most commonly used (129-190 million people), followed by amphetamine type stimulants, then cocaine and opioids.
- Psychoactive substance use can lead to dependence syndrome – a cluster of behavioural, cognitive, and physiological phenomena that develop after repeated substance use and that typically include:
- a strong desire to take the drug;
- difficulties in controlling its use;
- persisting in its use despite harmful consequences;
- a higher priority given to drug use than to other activities and obligations;
- increased tolerance, and sometimes a physical withdrawal state.
- Policies that influence the levels and patterns of substance use and related harm can significantly reduce the public health problems attributable to the problem, and interventions at the health care system level can work towards the restoration of health in affected individuals.
- The use of psychoactive substances causes significant health and social problems for the people who use them, and also for others in their families and communities.
- WHO estimated that 0.7% of the global burden of disease in 2004 was due to cocaine and opioid use, with the social cost of illicit substance use being in the region of 2% of GDP in those countries that have measured it.