Lessons learned from a randomized trial of fixed and escalating contingency management schedules in opioid-dependent pregnant women
Background: Contingency management (CM) has shown promise for treating substance use disorders in pregnant women. Methods: A randomized clinical trial compared the relative efficacy of three conditions on the measures of opioid and cocaine abstinence and days retained in treatment. A total of 133 pregnant patients attending treatment for substance use disorders were randomized either to an escalating reinforcement condition, a fixed reinforcement condition, or an attendance control condition. Conditions were compared on drug abstinence rates and days retained in treatment. Results: As expected, the pooled escalating + fixed conditions received a greater total amount of voucher money than the control condition mean [M = 392.40 (SE = 40.47) vs. 219.74 (SE = 39.78)], respectively; p < .001. However, the escalating and fixed conditions did not differ on the outcome variables of drug abstinence and treatment retention. Conclusions: The CM conditions examined in the current study did not emerge as superior to the control condition. The lack of significant differences among study conditions may be attributed, in part, to study sample size. Additionally, methodological issues related to the CM intervention may also have compromised outcomes, including delay in reinforcement following the target behavior and limited contact with the reinforcer. Scientific Significance: This study highlights the importance of key CM implementation features, including immediate reinforcement, and adequate access to the reinforcer. It may also be that the reset feature for missing samples in CM interventions is an essential contingency for promoting behavior change.