In modern, competitive societies the social organisation of ''youth'' implies both the chance and risk of (intergenerational) vertical social mobility. It is suggested that it is precisely this basic feature that to a considerable extent gives rise to substance use.In particular the paper aims at analysing the impact of the risk of educational downward mobility as well as some related characteristics. Using LISREL VI, it is shown that this type of educational career pattern, actual or anticipated, substantially contributes to the consumption of legal drugs. Weight is given to an extended analysis of the mode of action involved in the relationship between substance use and the career pattern as well as associated characteristics, respectively. As far as home is concerned, social conflict and associated feelings on the side of the adolescents turn out to be a major ''mechanism'' through which the observable impact of educational downward mobility can be traced back. Integration into both the cultural system of ''legalized'' drug use and subcultural contexts as provided by social cliques is a further condition that strongely influences substance use among adolescents.