Hypothyroidism
Page most recently updated 7 September 2026
This page focuses on the reported psychiatric associations, which may be the initial presenting manifestation, and on other clinical features that may assist the psychiatrist or primary care physician in identifying the underlying diagnosis, considered through the lenses of the diagnostic lenses framework.
Hypothyroidism is an endocrine disorder characterized by insufficient thyroid hormone activity, resulting in multisystemic effects.
It can present with psychiatric features such as depression, anxiety, cognitive slowing, impaired concentration, fatigue, mood disturbance, apathy, behavioural change, and, less commonly, psychosis (classically described as “myxedema psychosis”), particularly in the context of severe or prolonged hypothyroidism.
Other characteristic features include neurological manifestations such as cognitive impairment, slowed processing speed, somnolence, peripheral neuropathy, myopathy, and, in severe cases, myxedema coma with altered consciousness. Rarely, autoimmune thyroid disease may be associated with steroid-responsive encephalopathy associated with autoimmune thyroiditis (SREAT; formerly Hashimoto encephalopathy), which can present with encephalopathy, seizures, cognitive symptoms, and psychosis.
From a multisystemic lens perspective, clinical features in other body systems include (but are not limited to):
Cardiovascular: bradycardia, reduced cardiac output, diastolic hypertension, and hyperlipidaemia may occur.
Respiratory: reduced ventilatory drive, sleep-disordered breathing, and respiratory compromise may occur in severe hypothyroidism.
Renal/electrolytes: hyponatraemia may occur, particularly in severe hypothyroidism, due to impaired free water clearance.
Gastrointestinal: constipation and reduced gastrointestinal motility are characteristic.
Endocrine: autoimmune thyroid disease (particularly Hashimoto thyroiditis) is a common cause of hypothyroidism and may coexist with other autoimmune endocrine disorders.
Hematologic: anaemia may occur, including iron deficiency, vitamin B12 deficiency, or anaemia of chronic disease patterns depending on the underlying cause and associated autoimmune conditions.
Musculoskeletal: muscle cramps, proximal muscle weakness, stiffness, myalgias, and elevated creatine kinase due to hypothyroid myopathy may occur.
Dermatologic: dry skin, coarse hair, hair loss, brittle nails, and non-pitting oedema (myxoedema) are characteristic.
Early diagnosis is important to enable thyroid hormone replacement, treat reversible neuropsychiatric symptoms, prevent severe complications such as myxedema coma and cardiovascular morbidity, identify associated autoimmune disease where relevant, and improve prognosis and quality of life.
Selected references and further reading — Multisystemic lens
Cardinal RN, Bullmore ET. The diagnosis of psychosis. Cambridge: Cambridge University Press; 2011.
Sachdev PS, Keshavan MS, editors. Secondary schizophrenia. Cambridge: Cambridge University Press; 2010.
Levenson JL, editor. The American Psychiatric Association Publishing textbook of psychosomatic medicine and consultation-liaison psychiatry. 3rd ed. Washington (DC): American Psychiatric Association Publishing; 2019.
Stern TA, Beach SR, Smith FA, Freudenreich O, Vranceau AM, Fava M, editors. Massachusetts General Hospital handbook of general hospital psychiatry. 8th ed. Philadelphia: Elsevier; 2025.
Arciniegas DB, Yudofsky SC, Hales RE, editors. The American Psychiatric Association Publishing textbook of neuropsychiatry and clinical neurosciences. 6th ed. Washington (DC): American Psychiatric Association Publishing; 2018.
Agrawal N, Faruqui R, Bodani M, editors. Oxford textbook of neuropsychiatry. Oxford: Oxford University Press; 2020.
Boland R, Verduin M, editors. Kaplan and Sadock's comprehensive textbook of psychiatry. 11th ed. Philadelphia: Wolters Kluwer; 2024.
Loscalzo J, Fauci AS, Kasper DL, Hauser SL, Longo DL, Jameson JL, editors. Harrison's principles of internal medicine. 22nd ed. New York: McGraw Hill; 2025.