Locus of control in two samples of chronic drug abusers.
D002908:Chronic Disease; D006556:Heroin Dependence / Q000175:diagnosis; D006801:Humans; D007389:Internal-External Control; D010551:Personality; D011581:Psychological Tests; D012054:Reinforcement, Psychology; D012649:Self Concept; D019966:Substance-Related Disorders / Q000175:diagnosis*