Research findings suggest that alcoholism and drug abuse may be predisposed by inherited behavioral propensities or temperaments. These inherited predispositions, through interaction with the physical and social environments, shape the development of personality. As discussed herein, there is strong evidence linking certain personality characteristics, specifically antisocial and neurotic traits, with the risk for substance abuse. Thus, personality and its precursor, temperament, comprise an important diathesis. However, an adverse outcome also depends on a variety of developmental and environmental factors.The risk for developing a substance-abuse problem is not equally distributed in the general population. Numerous factors present in childhood augment the risk for the subsequent development of either an alcohol or a drug problem. Some of the most salient psychosocial risk factors include urban demographic status, low socioeconomic status, weak cultural-religious affiliation, easy access to drugs and alcohol, family history of alcohol or drug use, family discord, identification with a nonnormative peer group, alienation, and weak inculcation of nor-