Investigating Habituation to Premonitory Urges in Behavior Therapy for Tic Disorders

Abstract

Behavior therapy is effective for Persistent Tic Disorders (PTDs), but behavioral processes facilitating tic reduction are not well understood. One process, habituation, is thought to create tic reduction through decreases in premonitory urge severity. The current study tested whether premonitory urges decreased in youth with PTDs (N = 126) and adults with PTDs (N = 122) who participated in parallel randomized clinical trials comparing behavior therapy to psychoeducation and supportive therapy (PST). Trends in premonitory urges, tic severity, and treatment outcome were analyzed according to the predictions of a habituation model, whereby urge severity would be expected to decrease in those who responded to behavior therapy. Although adults who responded to behavior therapy showed a significant trend of declining premonitory urge severity across treatment, results failed to demonstrate that behavior therapy specifically caused changes in premonitory urge severity. In addition, reductions in premonitory urge severity in those who responded to behavior therapy were significant greater than those who did not respond to behavior therapy but no different than those who responded or did not respond to PST. Children with PTDs failed to show any significant changes in premonitory urges. Reductions in premonitory urge severity did not mediate the relationship between treatment and outcome in either adults or children. These results cast doubt on the notion that habituation is the therapeutic process underlying the effectiveness of behavior therapy, which has immediate implications for the psychoeducation and therapeutic rationale presented in clinical practice. Moreover, there may be important developmental changes in premonitory urges in PTDs, and alternative models of therapeutic change warrant investigation.

Trial registration: ClinicalTrials.gov NCT00218777 NCT00231985.

Keywords: behavior therapy; habituation; psychotherapy; tics.

Copyright © 2017. Published by Elsevier Ltd.

Figures

FIGURE 1

Proposed mediation path in which reductions in premonitory urges exert an indirect effect on the direct relationship between treatment assignment and treatment outcome (reductions in tic severity).

FIGURE 2

Repeated measures ANOVA of premonitory urge (PMU) trends across treatment in the child trial. Note: CBIT = Comprehensive Behavioral Intervention for Tics; PST = psychoeducation and supportive psychotherapy; PUTS = Premonitory Urge for Tics Scale. Data points reflect estimated marginal means and 95% confidence intervals.

FIGURE 3

Repeated measures ANOVA of premonitory urge (PMU) trends across treatment in the adult trial. Note: CBIT = Comprehensive Behavioral Intervention for Tics; PST = psychoeducation and supportive psychotherapy; PUTS = Premonitory Urge for Tics Scale. Data points reflect estimated marginal means and 95% confidence intervals.