Although social-environmental factors play a large role in the develop
ment of substance use and abuse, other important contributors reside w
ithin the individual. These intrapersonal factors help determine certa
in aspects of the social environment, which may in turn alter the prob
ability of drug use and abuse. In addition, these intrapersonal factor
s alter chances of initiation, the transition from initiation to regul
ar use of a drug, and the transition from regular drug use to problem
use. These factors include (but are not limited to) personality, cogni
tions, affect, problem behaviors, biogenetics, demographics, and bondi
ng. We explore the potential role of each of these intrapersonal facto
rs in a larger biopsychosocial model of drug use and abuse. We also di
scuss the implications of each of these factors for prevention.