PUB - Publikationen an der Universität Bielefeld

Over the last fifty years the use of psychoactive substances, both legal and illegal, has grown dramatically in the western societies, in particular among youths. Illegal drugs like marijuana have become widespread among the younger generations and the societal concern has grown with it. Initial research on the topic, although great in number, failed to measure and describe its development over time. More recently and with the advent of the Developmental Life-Course Criminology, the interest has moved from the aggregate to the individual. By means of growth mixture models (GMM) and latent transition analysis (LTA) it is now possible to study both the individual and aggregate development of substance use over a determined period of time. Using longitudinal data from the Crime in the Modern City Project, this study describes marijuana use among German adolescents over a time span of five years. More specifically: GMM are used to determine the existence of substantively different trajectories of drug use; LTA provides an adequate understanding of the transition patterns in the use of different types of substances. The results show, that, on the one hand, three trajectories are necessary to describe the development of marijuana use in the sample: a low-user (91%), an adolescence-limited (6%) and a desister trajectory (3%). On the other hand, latent transition analysis shows that marijuana acts as a gateway drug for more dangerous substances, whereas alcohol is the first substance to be used. These two models provide powerful tools for both a quantitative and a more "qualitative" approach to the study of substance use in its development over time.