Abstract
Myxedema psychosis (MP), a rare psychiatric manifestation of hypothyroidism, presents significant diagnostic and therapeutic challenges. This case report details the presentation, diagnosis, and successful management of a 60-year-old woman with MP, who was initially admitted to the psychiatric department for new-onset psychosis following the cessation of hormone replacement therapy after a subtotal thyroidectomy performed 20 years prior. Despite the rarity of psychosis as an initial presentation of hypothyroidism, this case underscores the critical importance of considering endocrine disorders in the differential diagnosis of unexplained psychotic symptoms. The clinical findings included a polymorphic delusional system and auditory hallucinations, without significant abnormalities on magnetic resonance imaging. Elevated thyroid-stimulating hormone (TSH) levels confirmed hypothyroidism, leading to the diagnosis of MP. Treatment with l-thyroxine resulted in complete resolution of symptoms in three weeks, highlighting the efficacy of hormone replacement therapy. This case contributes to the limited literature on MP and echoes the need for awareness among clinicians to ensure timely and accurate diagnosis and treatment.