Cannabis use has been found to have occurred as long ago as the third millennium B.C. In modern times, the drug has been used for recreational, religious or spiritual, and medicinal purposes. The United Nations (UN) estimated that in 2004 about 4% of the world’s adult population (162 million people) use cannabis annually, and about 0.6% (22.5 million) use it on a daily basis. The possession, use, or sale of cannabis preparations containing psychoactive cannabinoids became illegal in most parts of the world in the early twentieth century. Since then, some countries have intensified the enforcement of cannabis prohibition, while others have reduced it..