title: Trends in the age of onset of narcotic addiction.
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000428:Alcohol Drinking; D003061:Codeine; D003430:Cross-Sectional Studies; D006801:Humans; D013287:Illicit Drugs; D008297:Male; D008396:Maryland; D009293:Opioid-Related Disorders / Q000453:epidemiology*; D012306:Risk; D019966:Substance-Related Disorders / Q000453:epidemiology
chemical_list: D013287:Illicit Drugs; D003061:Codeine