Evaluating a dimensional approach to treatment resistance in anxiety disorders: A two-year follow-up study

Treatment resistance in anxiety disorders (TR-AD) has been previously defined by failed priortreatments and by various clinical aspects, but the impact of these aspects on course duringsubsequent treatments was never studied. Moreover, TR-AD was never studied using a dimensionalapproach. This study validated aspects of TR-AD and examined whether a TR-AD score was relatedto two-year course during treatment. From the NESDA cohort, anxiety disorder patients who subsequently received treatment wereselected (n=679). Literature-derived aspects of TR-AD at baseline included anxiety severity, functionalimpairments, psychiatric comorbidity, duration, and previous treatments. These were combined into adimensional TR-AD score. Individual aspects of TR-AD and the TR-AD score were linked to anxietydisorder persistence at two-year follow-up using logistic regression analyses. Predictive properties forthe TR-AD score were assessed. Current symptom severity, psychiatric comorbidity, functional impairments and previous duration ofsymptoms were closely associated with two-year anxiety disorder persistence, while treatment historywas not. The TR-AD score (10.8±2.3, range 2-23) was linked to two-year persistence (OR per pointincrement 1.29, p<0.01). The predictive properties of the TR-AD score appeared modest (AUC=0.66). In the current study, treatment history and ongoing treatments were retrospectively assessed. It wasnot evaluated whether prior treatments failed or succeeded. The results in the current study suggest that when assessing TR-AD and designing a treatment plan,evaluations of treatment history should be accompanied with assessments of clinical characteristics.The dimensional TR-AD measurement presented here could be used for this purpose.