title: Environmental theory of drug addiction.
mesh_terms: D000661:Amphetamine; D000818:Animals; D001923:Brain Chemistry; D004745:Enkephalins / Q000502:physiology; D006801:Humans; D007858:Learning; D008297:Male; D008568:Memory; D051379:Mice; D009021:Morphine Dependence / Q000503:physiopathology; D011817:Rabbits; D051381:Rats; D012931:Social Environment; D012934:Social Isolation; D019966:Substance-Related Disorders / Q000503:physiopathology / Q000523:psychology
chemical_list: D004745:Enkephalins; D000661:Amphetamine