Can hyperthyroidism (an overactive thyroid gland) mimic symptoms of anxiety disorder?

From the Guidelines

Hyperthyroidism can indeed mimic anxiety, as the symptoms of excessive thyroid hormone production, such as nervousness, irritability, and rapid heartbeat, closely resemble those of anxiety disorders. The relationship between hyperthyroidism and anxiety is complex, with some studies suggesting that thyroid hormone alterations may contribute to anxiety-related symptoms 1. According to a systematic review of the literature on hypothalamic-pituitary-thyroid (HPT) axis functioning in anxiety disorders, there is evidence for comorbidity between anxiety disorders and thyroid disorders on a subclinical level 1.

Key Findings

• The review found that patients with anxiety disorders may have altered HPT axis functioning, including diminished TSH responses to TRH challenge 1.
• The findings suggest that the co-occurrence of anxiety and thyroid dysfunction may be due to partly shared etiopathogenetic mechanisms, such as stress-related long-term alterations in the hypothalamic–pituitary–adrenal (HPA) axis 1.
• The review highlights the importance of considering thyroid testing, particularly measuring TSH and free T4 levels, to rule out hyperthyroidism as an underlying cause of anxiety symptoms 1.

Clinical Implications

• Healthcare providers should be aware of the potential for hyperthyroidism to mimic anxiety and consider thyroid testing in patients with anxiety symptoms.
• Treatment of hyperthyroidism with medications like methimazole or propylthiouracil, radioactive iodine therapy, or sometimes beta-blockers like propranolol may resolve anxiety-like symptoms.
• Distinguishing between primary anxiety disorders and thyroid-induced symptoms is essential for proper management, and some patients may temporarily need both thyroid treatment and anxiety management until thyroid levels normalize.

From the Research

Hyperthyroidism and Anxiety

• Hyperthyroidism can mimic anxiety, as it presents with similar symptoms such as anxiety, insomnia, palpitations, and unintentional weight loss 2, 3, 4.
• A case report highlighted the importance of evaluating endocrine causes in patients presenting with anxiety-like symptoms, as a 33-year-old female was initially misdiagnosed with generalized anxiety disorder before being diagnosed with hyperthyroidism 2.
• Studies have shown that hyperthyroidism can cause cardiac arrhythmias, heart failure, osteoporosis, and adverse pregnancy outcomes, and may lead to unintentional weight loss and increased mortality 4, 5.
• The most common cause of hyperthyroidism is Graves disease, and other causes include toxic nodules and the thyrotoxic phase of thyroiditis 4, 5.
• Adrenergic hyperactivity is a major cause of psychiatric symptoms in hyperthyroidism, and beta-adrenergic antagonists are effective treatment 6.
• Hyperthyroidism and syndromal depression-anxiety have overlapping features that can cause misdiagnosis during the acute phase, and differential diagnosis should be made by following up patients with hyperthyroidism with specific hormonal treatment and evaluating persisting symptoms thereafter 3.

Symptoms of Hyperthyroidism

• Common symptoms of thyrotoxicosis include anxiety, insomnia, palpitations, unintentional weight loss, diarrhea, and heat intolerance 4.
• Patients with Graves disease may have a diffusely enlarged thyroid gland, stare, or exophthalmos on examination 4.
• Patients with toxic nodules may have symptoms from local compression of structures in the neck by the thyroid gland, such as dysphagia, orthopnea, or voice changes 4.
• Psychomotor agitation, weight loss, and insomnia are discriminating symptoms for the hyperthyroidism group, whereas somatic anxiety and loss of interest are distinguishing symptoms of the euthyroidism group 3.

Diagnosis and Treatment

• Etiology of hyperthyroidism can typically be established based on clinical presentation, thyroid function tests, and thyrotropin-receptor antibody status 4, 5.
• Thyroid scintigraphy is recommended if thyroid nodules are present or the etiology is unclear 4.
• Treatment options for overt hyperthyroidism include antithyroid drugs, radioactive iodine ablation, and surgery 4, 5.
• Treatment choices should be individualized and patient-centered, and first-line treatments are antithyroid drugs, thyroid surgery, and radioactive iodine treatment 4, 5.