The purpose of this study is to evaluate the efficacy of prize-based contingency management (CM) when administered exclusively in groups. Substance dependent patients (N=360) at community-based treatment programs are randomly assigned to one of two conditions: (a) standard, non-CM treatment or (b) standard treatment plus prize CM delivered in groups. In the CM condition, patients earn the opportunity to win prizes for attending groups and submitting drug-free biological specimens. Substance use and psychosocial problems are measured at intake, month 1, month 3 (post treatment), and at 6-, 9-, and 12-month follow-up evaluations. We also assess patient characteristics that may be associated with improved outcomes within and across conditions.

Inclusion criteria:

• age > 18 years
• current DSM-IV diagnosis of cocaine, opioid or alcohol abuse or dependence
• willing to provide breath and urine samples for 12 weeks
• English speaking
• willing to sign informed consent

Exclusion criteria:

• serious, uncontrolled psychiatric illness (e.g., acute schizophrenia, bipolar disorder, severe or psychotic major depression, or suicide risk)
• dementia (<23 on the Mini Mental State Exam; Folstein et al. 1975)
• in recovery from pathological gambling