Neurobehavioral and psychological changes induced by hyperthyroidism: diagnostic and therapeutic implications.

Clinical studies have demonstrated that neuropsychiatric symptoms may be common and often the only symptoms of patients affected by hyperthyroidism. The correct diagnosis of hyperthyroidism is crucial for optimal treatment because the neuropsychiatric symptoms tend to parallel resolution as the biochemical parameters of hyperthyroidism are normalized. For these reasons, a routine evaluation in every patient consulting for emotional pathologies is recommended, independent of other manifestations of thyroid disease. The effect of high levels of thyroid hormones in the CNS has been related to changes in the presence of alpha- and beta-adrenergic postsynaptic receptors, or more recently to changes in the serotonin concentration. However, the available information is incomplete and many questions remain to be answered in order to explain how the thyroid hormone modifies the CNS response. Increased knowledge of the molecular targets (i.e., genes) of thyroid hormones in the brain may help to provide an answer to these questions.