Drug abuse as learned behavior.
D001007:Anxiety / Q000523:psychology; D003863:Depression / Q000523:psychology; D005794:Generalization, Response; D005795:Generalization, Stimulus; D006801:Humans; D007858:Learning; D008960:Models, Psychological; D010551:Personality; D012054:Reinforcement, Psychology; D019966:Substance-Related Disorders / Q000209:etiology* / Q000523:psychology