When Psychosis Conceals a Motor Crisis: A Misleading Case of Catatonia Unveiling Parkinson's Disease off Phenomenon.

Psychosis is a frequent comorbidity in Parkinson's disease (PD) and often complicates the evaluation of motor and behavioral fluctuations. Distinguishing between psychosis-related catatonia and a PD off phenomenon presents a significant diagnostic challenge. We describe the case of a 48-year-old male with PD and depression who was admitted to a psychiatric ward following an episode of aggressive behavior and persecutory delusions. During hospitalization, he developed mutism, rigidity, and immobility - initially interpreted as catatonia. A Bush-Francis Catatonia Rating Scale score of 16 was documented, but a lorazepam challenge failed to elicit improvement. These symptoms coincided with the tapering of dopaminergic therapy, particularly pramipexole. Neurological consultation on hospital day 11 identified the presentation as a severe PD off state. Restoration of dopaminergic therapy, focusing on extended-release formulations and optimized timing, resulted in marked clinical improvement within 1 week. Dopamine agonists were avoided due to concern for exacerbating psychosis. This case highlights the importance of distinguishing catatonia from PD off states in patients with overlapping motor and psychiatric symptoms. Careful medication history, response to benzodiazepines, and interdisciplinary collaboration are critical to diagnostic accuracy and treatment success.