Vouchers vs. Prizes for Cocaine-Dependent Methadone Patients - 2

Inclusion criteria: * age \> 18 years * current DSM-IV diagnosis of cocaine dependence * received methadone treatment at the clinic for at least 3 months * on a stable dose of methadone (no changes in dosing) for at least one month and not presently requesting a dose alteration * submitted one or more clinic-collected cocaine positive urine samples in the previous 3 months * English speaking * pass a brief quiz related to understanding of the informed consent form Exclusion criteria: * have a serious, uncontrolled psychiatric illness (e.g., acute schizophrenia, bipolar disorder, severe or psychotic major depression, or suicide risk) * have dementia (\<23 on the Mini Mental State Exam; Folstein et al. 1975) * are in recovery from pathological gambling