People with an overactive thyroid have higher levels of anxiety and depression than people with normal thyroid function, even when accounting for how often they see a doctor.
Mechanism
Synthesis from 1 study
When the thyroid makes too much hormone, it gets into the brain and speeds up the breakdown of mood-regulating chemicals. This makes the brain overactive and reduces the chemicals that help people feel calm and positive, leading directly to anxiety and depression.
Most probable mechanism
Too much thyroid hormone makes the brain more excitable and changes how brain chemicals like serotonin and norepinephrine work, which directly increases feelings of anxiety and sadness.
Elevated circulating thyroid hormones cross the blood-brain barrier and bind to nuclear receptors in neurons of the limbic system and prefrontal cortex.
Thyroid hormone upregulates the expression of monoamine oxidase enzymes in the brain, increasing the breakdown of serotonin, norepinephrine, and dopamine.
Increased neuronal excitability and reduced monoamine availability disrupt the regulation of emotional processing circuits, leading to sustained states of heightened arousal and negative affect.
Evidence from Studies
Supporting (1)
Community contributions welcome
Relationship of Stressful Life Events, Anxiety and Depression to Hyperthyroidism in an Asian Population
Contradicting (0)
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Gold Standard Evidence Needed
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