Intranasal esketamine as tool for rapid cycling bipolar disorder: A case report of successful mood stabilization

Rapid Cyclic Bipolar Disorder (RCBD) is a debilitating condition that manifests as four or more episodes of depression, mania, or hypomania in a span of one year, with depression being the predominant event. RCBD is prevalent among individuals diagnosed with bipolar disorder and is associated with elevated suicide risk, prolonged disease duration, unfavorable clinical outcomes, and cognitive decline. The treatment of RCBD is challenging, owing to the poor response to lithium and other conventional treatments for bipolar disorder and the possibility of exacerbating rapid-cycling oscillations during depressive phases with the use of antidepressant therapies. Esketamine Nasal Spray (ESK-NS) has been approved for the treatment of Treatment-Resistant Depression but its application in the context of RCBD is limited and unknown. This study presents the case of a 56-year-old male diagnosed with RCBD who received ESK-NS treatment during a depressive episode and was followed up for 18 months. During the observation period, the subject exhibited a significant mood stabilization, with only a transient depressive episode observed during a three-month period of cessation of ESK-NS treatment, which promptly resolved upon reinstating ESK-NS therapy. Mild dissociative symptoms were observed during the initial doses of ESK-NS administration, but no other significant adverse events were reported. This case report provides initial evidence for the potential utilization of ESK-NS in the treatment of RCBD, supporting the hypothesis of an additional mood-stabilizing effect.