The study examined drug consumption patterns and conditioning factors on the basis of Primary Socialization Theory, through the application of a questionnaire to a representative sample (N = 650) of the young population (age 15 to 29 years) in the Madrid Region. Cluster analysis identified five consumption groups. Discriminant analysis, including indicators about subjects' integration in primary socialization environments, beliefs about the effects of drugs, indicators of psychosocial wellbeing, and variables related to leisure time, allowed 67.45 percent of correct consumption group prediction. The study found complex associations between drug use, socialization environments, and psychosocial wellbeing. This called into question approaches establishing cumulative or unidimensional relationships between posited "risk factors" and drug consumption. The study concludes that Primary Socialization Theory appears to offer an appropriate structure to guide analysis of the variables identified at the different conceptual levels and to offer coherent explanations for results previously considered confused or ambiguous. Tables, figures, notes, references