Psychosis as the Initial and Main Presentation of Graves' Disease: A Case Report from Saudi Arabia.

Although psychosis is an uncommon manifestation of thyrotoxicosis, it may precede typical somatic features, leading to diagnostic delay. Recognition of its endocrine origin is crucial, as symptoms are usually reversible with appropriate treatment. A 29-year-old woman with no prior psychiatric or medical history presented with persecutory delusions, religious preoccupation, and auditory hallucinations in the absence of mood, cognitive, or classic somatic thyrotoxic symptoms. Examination revealed mild exophthalmos without other thyrotoxic signs. Laboratory tests showed suppressed thyroid-stimulating hormone (TSH; <0.005 mIU/L), elevated free triiodothyronine (T3; 30.5 pmol/L), and positive thyroid autoantibodies, confirming Graves' disease. She was treated with carbimazole and atenolol, alongside low-dose olanzapine (5 mg daily). Her psychotic symptoms resolved completely concurrently with the normalization of thyroid function. This case illustrates that psychosis may be the initial and sole presentation of Graves' disease. The close temporal relationship between biochemical improvement and symptom resolution supports a direct link between thyrotoxicosis and psychosis. Short-term, low-dose antipsychotics can be useful adjuncts during acute management but are rarely needed long-term once euthyroidism is achieved. Endocrine screening should be routinely performed in new-onset psychosis to identify reversible causes such as thyrotoxicosis. Early recognition and treatment of underlying hyperthyroidism ensures rapid psychiatric recovery and prevents unnecessary prolonged antipsychotic use.