Science Cannabis

212 THE SCIENCE OF MARIJUANAfor 18-year-olds in the United States and many European countries thisfigure rises to almost 50%.Patterns of consumption over the years have varied differently invarious countries. In the United States, statistics provided by the NationalInstitute on Drug Abuse through their Monitoring the Future Study givea detailed picture of cannabis use among teenagers. Cannabis becamevery popular among young people in the United States during the 1970s,reaching a peak in 1979 when more than 60% of 12th grade students inAmerican high schools (average age 18) admitted ever having used thedrug, and 10% reported that they were daily users. There was then amarked drop in consumption during the 1980s. Consumption has, however,increased again rapidly during the 1990s, and among teenagers itnow approaches the 1979 levels (Fig. 6.1). The results of a study publishedin 1997 gave data on a postal survey of 17,592 students at 140American colleges (Bell et al., 1997). One in four of the students whoresponded (24.8%) reported using marijuana during the past year. The1990s saw a particularly sharp increase in cannabis use by younger people,from 10% in 1991 to 23% in 1997 among American 8th grade students(average age 14) who admitted to ever having used the drug. Patternsof consumption in most European countries have lagged somewhatbehind those in the United States but most countries did not experiencethe substantial drop in consumption seen in the United States during the1980s. Current levels of consumption in Europe are now similar to thosein the United States.The great majority of people who try cannabis do so experimentally.Unlike tobacco, where a high proportion of first time users go on tobecome lifetime smokers, most cannabis users do not go on to becomeregular users of the drug. Thus, 1996 data in the United States show thatwhile 68.6 million people (32%) admitted having used cannabis once,only 18.4 million (8.6%) reported having used the drug during the pastyear. In Britain in 1994, 20% admitted ever having used cannabis, butonly 5% had used the drug during the past year. It is difficult to assesshow many people are regular users of cannabis. There is no agreed definitionof "regular user," it could mean anything from someone who tookthe drug a few times a year on special occasions, to someone consuming