Environment and drug abuse.
D000437:Alcoholism / Q000209:etiology / Q000235:genetics*; D004777:Environment; D006801:Humans; D008297:Male; D019966:Substance-Related Disorders / Q000209:etiology / Q000235:genetics*; D018433:Twin Studies as Topic; D014429:Twins, Dizygotic; D014430:Twins, Monozygotic