The results showed that early maturers and late maturers had more advanced drinking habits at age 14 as compared to their normally maturing same-aged peers (p less than .05). This difference was not significant 1 and one half years later. In young adulthood more than one third (36 percent) of the late maturers were registered for alcohol abuse as compared to 14 percent of the normal maturers and eight percent of the early maturers (p equals .12). The relevance of psychosocial factors as mediating the relationship between biology and actual behavior was discussed. It was emphasized that differences in biological and psychosocial maturity should be taken into consideration when studying adolescent behavior, both in cross-sectional and in longitudinal perspectives. 30 references. (Author abstract)