Several personality needs have consistently been identified as placing adolescents at heightened risk for the relatively intensive use of alcohol and other drugs. At the same time, little is known about the natural history of personality change during adolescence as it relates to substance use behaviors. Yet, this question is of clear importance to our understanding of personality risk factors for substance use because personality needs appear less temporally stable during adolescence than later in the life span. In this study, we use prospective longitudinal data to investigate the relation of high-risk personality needs to substance use in two groups of adolescents: those who maintained a temporally stable personality need structure across 3 years and those who showed considerable changes in personality needs during the same time interval. Subjects were 12, 15, or 18 years old at the first test time and 15, 18, or 21 years old, respectively, at the second test time. For subjects of both sexes, only those who maintained a temporally stable, low-risk personality profile showed quite conservative substance use patterns across time compared with all others. Generalized personality changes were linked to more intensive substance use behaviors in males, especially among those who had high levels of risky personality needs at the first test time. In contrast, personality change, per se, did not appear as relevant to females' alcohol and other drug use behaviors until combined with information regarding their level of high-risk personality needs. The results are discussed in terms of their implications for prevention and future research.