Since 1997, the United Nations Office on Drugs and Crime (UNODC) has published estimates of the extent of drug misuse in the world. The most recent figures presented estimated that about 200 million people, comprising five per cent of the world’s population aged 15 to 64, used drugs at least once in the last 12 months (UNODC, 2007). Cannabis was found to have been consumed by approximately 160 million people or 4 per cent of the population aged 15 to 64. At the global level, the main addictive drugs reported were opiates and cocaine (consumed by approximately 0.4 per cent [15.6 million] and 0.3 per cent [14.3 million] of the world population respectively).