Hypothyroidism is associated with changes in mental state that can range from mild cognitive impairment to depression to florid myxedema coma. A few cases have linked the occurence of psychotic symptoms in the context of severe hypothyroidism, an event referred in the literature as “myxedema madness”. We describe the case of a 48-year-old male with no past psychiatric history and a past medical history of hypertension and hypothyroidism who presented to the psychiatric unit for management of new-onset psychosis, particularly paranoid delusions. On basic medical screening, the patient was found to have severe hypothyroidism manifested by a TSH level of 51.85 and a free T4 level less than 0.4. The patient was treated with both an antipsychotic and thyroid hormone replacement, after which his hypothyroid symptoms and his psychosis improved. Liothyronine was also prescribed to speed up the recovery course, as his delusions were thought to be due to his hypothyroidism. The aim of this poster is to shed light on the possibility of development of psychosis concomitantly with severe hypothyroidism, given the rarity of such events, as well as to illustrate the importance of treating the underlying medical cause rather than only focusing on the treatment of the psychiatric symptoms. The use of Liothyronine proved to be beneficial in this case, as the patient's symptoms drastically improved after its administration. This could potentially illustrate the importance of using Liothyronine particularly in the treatment of delusional disorder in severe hypothyroidism.