Prevention efforts in alcohol and drug abuse have typically focused on the general population. However, most individuals who abuse addictive drugs either terminate consumption voluntarily or do not progress to a clinical diagnosis of psychoactive substance use disorder (PSUD). Because PSUD has such adverse effects on costs to society, prevention research and practice should emphasize the development and implementation of interventions for individuals who are at high risk for this disorder. This article proposes a conceptual framework for better understanding of the etiology of PSUD and for implementing prevention efforts that are targeted to specific vulnerabilities of an individual. These vulnerabilities are discussed with respect to their spatial organization (i.e., manifestations across multiple levels of biobehavioral organization) and temporal organization (i.e., manifestations across an individual's life span).