Could you tell me if untreated is there any danger of a person having thyroid problem becoming a psychotic?

Yes: There is an old term called myxedema madness which referred to the combination of edema ( throughout the body particularly noticeable in face and legs ) along with psychotic symptoms all due to hypothyroidism ( low thryoid functioning ) there also can be manic and psychotic symptoms in cases of hyperthyroidism (overactive thyroid functioning) . A blood test can usually help make the diagnosis.