Randomized controlled trial of contingency management for stimulant use in community mental health patients with serious mental illness

Abstract

Objective: 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.

Method: 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.

Results: 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.

Conclusions: 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.

Trial registration: ClinicalTrials.gov NCT00809770.

Figure 1. Study consort diagram

Figure 2. Percent of participants with stimulant-negative urine samples across the baseline (week 0) and 12-week treatment periods

Note: Those assigned to the contingency management group were 2.4 (CI=1.9-3.0, p<0.05) more likely to submit a stimulant-negative urine test, relative to those in the non-contingent control group during the 12-week treatment period. While the use of multiple imputation techniques allowed for us to include the entire sample (N=176) in our inferential statistical tests of treatment outcomes, the original raw data (without imputation) are displayed in this Figure.