A randomized study of contingency management in cocaine-dependent patients with severe and persistent mental health disorders.

Background: Contingency management (CM) is efficacious for reducing drug use, but it has rarely been applied to patients with severe and persistent mental health problems. This study evaluated the efficacy of CM for reducing cocaine use in psychiatric patients treated at a community mental health center.

Methods: Nineteen cocaine-dependent patients with extensive histories of mental health problems and hospitalizations were randomized to twice weekly urine sample testing with or without CM for 8 weeks. In the CM condition, patients earned the chance to win prizes for each cocaine-negative urine sample. Patients also completed an instrument assessing severity of psychiatric symptoms pre- and post-treatment.

Results: Patients assigned to CM achieved a mean (standard deviation) of 2.9 (1.7) weeks of continuous cocaine abstinence versus 0.6 (1.7) weeks for patients in the testing only condition, p=.008, Cohen's effect size d=1.35. Of the 16 expected samples, 46.2% (27.5) were cocaine negative in the CM condition versus 13.8% (27.9) in the testing only condition, p=.02, d=1.17, but proportions of negative samples submitted did not differ between groups. Reductions in psychiatric symptoms were noted over time in CM, but not the testing only, condition, p=.02.

Conclusions: CM yielded benefits for enhancing durations of abstinence in dual diagnosis patients, and it also was associated with reduced psychiatric symptoms. These findings call for larger-scale and longer-term evaluations of CM in psychiatric populations.