[Treatment resistance in anxiety disorders-Definition and treatment options]

Treatment resistance in anxiety disorders represents a clinical challenge, contributes to the chronicity of the diseases as well as sequential comorbidities, and is associated with a significant individual and socioeconomic burden. This narrative review presents the operational definition of treatment resistance in anxiety disorders according to international consensus criteria (< 50% reduction in the Hamilton Anxiety Scale, HAM‑A, score or < 50% reduction in the Beck Anxiety Inventory, BAI, score or a clinical global impression-improvement, CGI‑I, score > 2). At least two unsuccessful guideline-based treatment attempts with pharmacological monotherapy or at least one unsuccessful treatment attempt with adequately delivered cognitive behavioral therapy are required. Pharmacotherapeutically, after excluding pseudo-resistance, switching the medication within one class or to another class and augmentation strategies with other antidepressants (mirtazapine, agomelatine), antipsychotics (quetiapine) or anticonvulsants (valproate) are recommended. Psychotherapeutically, third-wave therapies, psychodynamic therapy, systemic therapy and physical exercise can be considered for therapy resistance. In cases of no response to psychotherapy or pharmacotherapy, the respective other form of therapy or a combination of both should be offered. Compounds targeting the glutamatergic and endocannabinoid systems as well as neuropeptides are being tested as potential innovative pharmaceuticals for treatment-resistant anxiety disorders. There is an urgent need for further research to identify predictive markers and mechanisms as well as to develop innovative pharmacological and psychotherapeutic interventions for treatment-resistant anxiety disorders.