Treatment failure in persistent tic disorders: an expert clinicians' consensus-based definition

A standardized definition of treatment failure in the management of tics is currently lacking. Such definition would prevent persistent use of unnecessary interventions and help clinicians to determine when to offer less established treatments (e.g., deep brain stimulation surgery). To achieve an expert consensus-based definition of failure of medical treatments for tics, we used a multi-step, multi-round, web-based Delphi approach involving international specialist clinicians with specific expertise in tic disorders. These experts were identified through professional networks or consortia related to chronic tic disorders. We created a survey and reviewed the questions with stakeholders prior to two rounds of Delphi surveys, followed by a final review and discussion among research team members. Both survey rounds were completed using a sample of 36 expert stakeholders from 14 countries, including neurologists, psychiatrists, and clinical psychologists. The Delphi process led to consensus on 10 statements which formed the final definition of treatment failure. The definition was structured and operationalized according to two separate sections, one for behavioral and one for pharmacological treatments. Core components of the definition and its operationalization included lack of efficacy, adherence, and tolerability, as well as a definition of failure of behavioral therapies as a whole, and of pharmacological therapies as a whole. The group concluded that the components of this specific definition reflect the range and complexity of characteristics to consider in establishing tic-related treatment failure. Future research should assess the feasibility of this operational definition and whether it will change clinical decision-making and improve management outcomes.