Changes in use of crack cocaine after drug misuse treatment: 4-5 year follow-up results from the National Treatment Outcome Research Study (NTORS).

Crack cocaine outcomes at 4-5 years are reported for 496 drug users recruited from UK treatment programmes. About one-third used crack at intake and at 4-5 years. The results show different outcome profiles. For crack users at intake, use was more than halved at follow-up. Among non-crack-users at intake, about a quarter used crack during follow-up, of whom about two-thirds had never used crack before. Polydrug use and use of other stimulants were associated with using crack. Crack users reported worse acquisitive crime and psychological health outcomes. About 10% reported injecting crack. The reductions in crack use are encouraging, but the onset of crack use among many non-users at intake suggests the need to develop more effective treatment interventions.