Cigarette smoking as a precursor of illicit drug use.
D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000437:Alcoholism / Q000453:epidemiology / Q000209:etiology; D002188:Cannabis; D003042:Cocaine; D006801:Humans; D007266:Inhibition, Psychological; D008297:Male; D009892:Opium; D012907:Smoking / Q000150:complications / Q000523:psychology*; D019966:Substance-Related Disorders / Q000453:epidemiology / Q000209:etiology
D009892:Opium; D003042:Cocaine