Fahr's disease is a rare neurological disease that typically presents with neurological manifestations such as movement disorders. In a first recorded patient with Fahr's disease in Bhutan, psychiatric diagnosis of bipolar affective disorder with current episode of severe depression was made, which is also a known manifestation of Fahr's disease. Diagnosing a first case of Fahr's disease is important for Bhutan because, though, it is a rare disease and it emphasizes the importance of recognizing other rare causes of psychiatric illness to tailor the treatment to the individual.