Comparing Fixed-Amount and Progressive-Amount Schedules of Reinforcement for Tic Suppression

Abstract

Chronic tic disorders (CTDs) involve motor and/or vocal tics that cause substantial distress and impairment. Existing behavioral interventions for CTDs have comparable efficacy to pharmacological treatments but still leave many individuals with significant tic symptoms and impairment. One approach to improving existing treatments involves conducting pre-clinical laboratory research to evaluate procedures that may be attractive candidates for applied treatment research. Reinforcing tic suppression via differential reinforcement of other behavior (DRO) procedures produces decreases in tic frequency of ~80% in youth with CTDs; however, a more robust reduction may be needed to affect durable clinical change. The present study compared the effects of a novel, progressive-amount DRO schedule for tic suppression and a standard DRO schedule representative of that used in previous research. Five youth with CTDs were exposed to periods of baseline, traditional/fixed-amount DRO (DRO-F), and progressive-amount DRO (DRO-P). Both DRO schedules decreased tic rate and inter-tic interval duration. However, no systematic differences between the two DRO schedules were observed on measures of tic occurrence, premonitory urge strength, or subjective stress. The DRO-F schedule was generally preferred to the DRO-P schedule. The DRO-P procedure did not yield more desirable effects than the DRO-F schedule. Basic and applied implications of this study and future directions for CTD treatment development research are discussed.