Clinical and Neurobiological Findings in a Patient With Unipolar Depressive 48-hour-ultrarapid-cycling

The rare cases of patients with 48-hour bipolar or unipolar ultra-rapid-cycling allow a more precise understanding of mood cycles in affective disorders, as the rhythmic changes in the psychopathological state and biological parameters are quite precise.

A 73-year-old male patient with several years of recurrent affective-depressive disorder (International Classification of Diseases, 10th Revision: F33.1) developed unipolar 48-hour-ultra-rapid-cycling with 1 day of severe depression up to acute suicidality and 1 day of euthymia (International Classification of Diseases, 10th Revision: F31.8) at the beginning of 2024.

Ultra-rapid-cycling could be objectified both psychopathologically (Beck Depression Inventory and visual analogue scale) and neurobiologically (especially serotonin using loudness dependence of auditory evoked potentials) at the end of the year. The patient responded promptly to the subsequent adjustment to 900 mg daily lithium and has been symptom-free and with-out a 48-hour rhythm ever since.

Unipolar depressive 48-hour-ultra-rapid-cycling of marked mood and drive fluctuations is also associated with characteristic biological changes, and that lithium represents a successful treatment strategy here in contrast to "normal" rapid-cycling.