Esketamine nasal spray reduced depressive symptoms in people with treatment-resistant bipolar depression as effectively as in those with unipolar treatment-resistant depression, with no significant differences in response or remission rates after one and three months. The treatment also showed greater anxiety-reducing effects in the bipolar group. No treatment-emergent affective switch occurred, supporting the safety and tolerability of esketamine for bipolar treatment-resistant depression.
Among patients with treatment-resistant depression who continued esketamine nasal spray for at least six months, 76.2% responded or achieved remission. Of those who had not responded by six months, a subset improved by twelve months. Side effects occurred in 71.8% of patients at six months, decreasing to 42% at twelve months; the most common were sedation and dissociation. Only two patients stopped treatment due to tolerability issues. The findings suggest esketamine is effective and safe for mid- to long-term treatment, with a novel observation of late clinical response in some patients. Results require confirmation in larger samples and longer observation periods.