[Epidemiological study of cannabis abuse and dependence in 256 adolescents]

A study of cannabis use in French adolescents was implemented using a questionnaire derived from the French version of the Mini International Psychiatric Interview based on DSM IV criteria for cannabis dependence, among a population of 256 high school students from two high schools with different SES backgrounds. Among the adolescents studied, 41.4% (n = 106) reported using cannabis occasionally or regularly, 51.2% had never used cannabis, and 7.4% had used cannabis and subsequently quit. Incidence of usage appeared to increase as a function of age, 51.4% for those 18 years and over, 44.6% for 17 years-old, and 30.4% for 16 years-old, girls tending to consume less than boys (36.4% to 45.2%). With regards to results of the MINI, of the regular or occasional users (n = 106), 47.2% of the subjects indicated substance dependence while the remaining subjects indicated that they were recreational users only. Among users, data concerning tolerance, withdrawal, and excessive consumption indicated that subjects were significantly affected by their addictive behavior; 33% of users reported having smoked cannabis for one year or less with 10.4% reporting that they have smoked for more than three years. Among those having smoked one year or less, 31.4% reported signs of dependence versus 68.6% who consume on a recreational basis; among those having used cannabis for three years or more, 63.6% reported dependence while 36.4% admitted to recreational usage. This study indicates the seriousness of cannabis usage among high-school students, underlining addictive and dependent behavior and their effects on daily life as well as significant the increase of usage with age and as a function of number of years of smoking.