Middle-aged man with primary hyperparathyroidism-associated psychosis: A case report.

Background: Primary hyperparathyroidism (PHPT) with mild hypercalcemia (Ca <12 mg/dL) often remains asymptomatic. However, PHPT may induce various psychiatric symptoms, including depression, cognitive dysfunction, and infrequently, psychotic symptoms, predominantly in older adults rather than in middle-aged or younger individuals.

Case‐presentation: A 48-year-old man, with no history of physical or mental illness, experienced delusions about a suspicious car in his neighborhood, believing it was linked to criminal activity. This led to his being taken into custody after harming himself and his family. He was admitted for psychiatric evaluation and diagnosed with PHPT after mild hypercalcemia was discovered. He was initially treated medically for the mild hypercalcemia; however, only his disorientation showed improvement, and his broader psychiatric symptoms persisted. His delusions ceased only after surgical intervention. Following discharge, he remained symptom-free without requiring antipsychotic medication.

Conclusion: This case highlights the importance of considering PHPT in patients of any age presenting with psychosis, even with mild hypercalcemia. Surgical options for patients with PHPT should be considered when medical interventions fail.