In Norway, the use of cannabis was introduced by a resourceful group of oppositional middle-class adolescents in the late 1960s. At the beginning of the 1970s there were, however, signs of a change in the recruitment of the users: youths in trouble from lower social levels gradually started to use the drug. In a prospective longitudinal study of 1311 Norwegian pupils aged 13-19, the possible links between normative and political opposition, mental health and the use of cannabis were investigated. The findings indicate that the group that experiments with cannabis, and use the drugs a few times, is still mainly characterized by a political and normative "oppositional" engagement. Heavy users of cannabis, however, also have family problems and suffer from poor mental health. Thus, the study draws attention to the importance of distinguishing between two different clusters of longitudinal predictors for adolescent cannabis use: the first consists of subcultural opposition and certain personality traits, and seems to predict the earlier stages of use. The second consists of psychosocial problems and poor mental health. From this study one may not conclude that this second cluster predicts heavy cannabis involvement. We have, however, shown that it correlates with heavy involvement, cross-sectionally.