Harmful use of psychoactive substances is a pattern of use that is causing damage to physical and/or mental health. Psychoactive substance use and substance use disorders can result in a wide range of problems for individuals, their families and wider community (WHO 2004). Worldwide, about two billion people use alcohol. Between 172 and 250 million people used illicit drugs at least once in 2007. Harmful alcohol use accounts for 4.5% of the global burden of disease and is responsible for 3.8% of all deaths (WHO 2009).