The long-term development of substance use and abuse in girls and women are poorly understood. In at least two ways, females compared to males appear more vulnerable to substance abuse and dependence: a speedier development from onset of use to abuse, and a higher propensity to develop comorbid conditions. In addition, females and males with an early onset of substance use are more likely to become substance abusers. The main goal of the proposed research is to investigate the early phases in this development process. Specifically, we propose to study precursors to the onset of early substance use (i.e., mainly alcohol and tobacco use), the transition to onset of use, and the transition to regular use in an inner-city community sample of 2,484 preadolescent girls. The girls, together with their parent and school teacher, will be assessed yearly and will be followed up over a period of five years. The sample will be made up of approximately 50 percent African-American and 50 percent Caucasian girls. The proposed study will be a substudy linked to and benefitting from the NIMH-funded study on the same girls, which has as its main object the study of the development of antisocial and delinquent behavior. The present proposal has three foci: 1). To identify the developmental precursors to the onset and regular use of substances; 2). To examine behavior problems which interact with early substance use; and 3) To elucidate the risk and protective factors predictive of the precursors of early substance use and predictive of the early use. The proposed study will be the foundation upon which follow-ups beyond the current five-year period can be built in order to better understand the long-term antecedents, risk and protective factors for substance abuse and dependence in females.