The primary objective of this study was to determine whether contingency management was associated with increased abstinence from stimulant drug use in stimulant-dependent patients with serious mental illness treated in a community mental health center. Secondary objectives were to determine whether contingency management was associated with reductions in use of other substances, psychiatric symptoms, HIV risk behavior, and inpatient service utilization.
A randomized controlled design was used to compare outcomes of 176 outpatients with serious mental illness and stimulant dependence. Participants were randomly assigned to receive 3 months of contingency management for stimulant abstinence plus treatment as usual or treatment as usual with reinforcement for study participation only. Urine drug tests and self-report, clinician-report, and service utilization outcomes were assessed during the 3-month treatment period and the 3-month follow-up period.
Although participants in the contingency management condition were significantly less likely to complete the treatment period than those assigned to the control condition (42% compared with 65%), they were 2.4 times (95% CI=1.9–3.0) more likely to submit a stimulant-negative urine test during treatment. Compared with participants in the control condition, they had significantly lower levels of alcohol use, injection drug use, and psychiatric symptoms and were one-fifth as likely as those assigned to the control condition to be admitted for psychiatric hospitalization during treatment. They also reported significantly fewer days of stimulant drug use during the 3-month follow-up.
When added to treatment as usual, contingency management is associated with large reductions in stimulant, injection drug, and alcohol use. Reductions in psychiatric symptoms and hospitalizations are important secondary benefits.