Compassionate use of esketamine intranasal in patients with severe major depressive disorder resistant to the treatment.

Background: Treatment-resistant depression (TRD) is defined as the failure of at least two antidepressants in adequate doses and timing during a major depressive episode. Esketamine intranasal (ESK-IN) has been approved by the Food and Drug Administration and the European Medicines Agency for the treatment of TRD in combination with other antidepressants.

Aims: To assess the effectiveness and tolerability of a sample of TRD patients who received treatment with ESK-IN as part of the compassionate use program.