['Drug addiction and alcoholism involve a complex etiopathogenesis with a variable degree of risk contributions from the host (person), environment, and addictive substances. In this work, temperament and character features of individuals addicted to opiates or alcohol are compared with normal controls to study personality factors in the overall risk for drug addiction.', 'The study was done in a permissive environment, with easy access to alcohol and heroin, which facilitated analyses of personality factors in drug choice. Participants included 412 consecutive patients (312 opiate addicts, 100 alcohol addicts) treated at the Specialized Hospital for Chemical Dependency in Belgrade, Serbia, and a community sample of 346 controls.', 'Opiate addicts manifested antisocial temperament configuration (high Novelty Seeking, low Reward Dependence) coupled with high Self-transcendence (ie, susceptibility to fantasy and imagination). Alcohol addicts manifested sensitive temperament configuration (high Novelty Seeking coexisting with high Harm Avoidance). Immature personality was observed far more frequently in opiate addicts than in alcoholics or normals.'] Do temperament and character modify risk of drug addiction and influence choice of drugs?