Tolerating Uncertainty as a Transdiagnostic Construct and Treatment Target in Functional Motor Disorder.

BackgroundIntolerance of Uncertainty (IU) has never been explored in functional motor disorder (FMD) or any functional neurological disorder but perceptions of control are theoretically relevant.ObjectiveTo evaluate if IU changes in people with FMD completing intensive 1-week motor retraining treatment, and if IU change associates with outcome.MethodsA consecutive cohort of 45 FMD patients completed a 1-week intensive outpatient motor retraining treatment. At program beginning and end, patients self-rated IU using the Intolerance of Uncertainty Scale-12 (IUS-12) and four functional impairment measures. Paired t-tests analyzed program changes in IU and functional outcomes. Linear regressions analyzed association strength between IU change and outcome.ResultsIU improved with FMD treatment (p < 0.001). Pre- to post-treatment IU was improved in 32/45 (71%), stable in 5/45 (11%), and worsened in 8/45 (18%). Age, symptom duration, and FMD phenotype did not predict IU improvement. Self-rated function improved across measures with treatment (p < 0.001). Program change in IU positively predicted outcome on 3 of 4 measures.ConclusionsIU improves with FMD rehabilitation, even without explicit psychological focus of treatment, regardless of age or FMD phenotype. Improving IU associates with positive FMD treatment outcomes suggesting an important treatment target in FMD.