Thyroid disease and mental disorders: cause and effect or only comorbidity?

Area of Science:

• Neuroendocrinology
• Psychiatry
• Genetics

Background:

• Thyroid hormones are crucial for brain development and function.
• Thyroid dysfunction, including hypothyroidism and hyperthyroidism, is prevalent and associated with various neurological and psychiatric symptoms.
• Thyroid autoimmunity may also play a role in mental health disorders.

Purpose of the Study:

• To review the effects of thyroid dysfunction and autoimmunity on mental symptoms and disorders.
• To integrate recent epidemiological, clinical, and genetic findings.
• To explore the relationship between thyroid disease and mental health in patients.

Main Methods:

• Review of recent epidemiological data.
• Analysis of clinical findings in patients with thyroid disease.
• Examination of genetic factors influencing mental symptoms and treatment outcomes.

Main Results:

• Iodine deficiency, maternal thyroid dysfunction, and neonatal thyroid issues contribute to neurological deficits during development.
• Adults with thyroid dysfunction commonly experience mental symptoms; adrenergic hyperactivity is key in hyperthyroidism.
• Genetic factors, including polymorphisms in deiodinase and transporter genes, influence hypothyroidism's mental symptoms and treatment response.

Conclusions:

• Brain-thyroid relationships remain important in adults, though less apparent than in developing brains.
• Adrenergic hyperactivity is a primary driver of psychiatric symptoms in hyperthyroidism.
• Genetic factors are significant in the development and treatment of mental disorders associated with hypothyroidism.