Working Mechanisms of Exposure and Response Prevention in the Treatment of Tourette Syndrome and Tic Disorders Revisited: No Evidence for within-Session Habituation to Premonitory Urges

Exposure and response prevention (ERP) has been shown to be an effective treatment for Tourette syndrome (TS) and chronic tic disorders (CTD). ERP is based on voluntary tic suppression in combination with prolonged exposure to premonitory urges preceding tics. A prevailing hypothesis of the working mechanism underlying ERP in tics is habituation to the premonitory urges as a result of prolonged exposure. However, results so far are equivocal. This study aims to further explore the relation between urges and ERP in tics, by investigating the course of premonitory urges during ERP sessions. Using a data-driven approach, within-session habituation to premonitory urge intensity was investigated. In total, 29 TS patients rated urge intensity at seven timepoints during ten 1 h ERP sessions. Latent growth modeling showed an increase in urge intensity during the first 15 min of each session followed by a plateau in the remaining 45 min of the session. This does not support the idea of within-session habituation to premonitory urges as a working mechanism of ERP. Other potential underlying working mechanisms are discussed and should be tested in future research.