title: Studying addicts over time: methodology and preliminary findings.
mesh_terms: D000328:Adult; D001741:Black or African American; D000367:Age Factors; D005500:Follow-Up Studies; D006556:Heroin Dependence / Q000453:epidemiology / Q000401:mortality / Q000534:rehabilitation; D006753:Hospital Records; D006801:Humans; D008297:Male; D008396:Maryland; D011157:Population Dynamics; D011996:Records; D012107:Research Design; D012926:Social Control, Formal; D011795:Surveys and Questionnaires; D013997:Time Factors