Purpose of review 

The brain is an important target organ for thyroid hormone, and alterations in mood and cognition may occur with thyroid dysfunction. Recent advances in the field of cognitive neurosciences have allowed more sensitive and focused testing of cognitive domains in patients with altered thyroid function.

Recent findings 

Based on recent population-based studies, there do not appear to be major deficits in cognitive functioning in overt or subclinical thyroid disease. However, interventional and functional imaging studies suggest that subtle deficits in specific cognitive domains probably do exist. The most commonly affected domains are working memory and executive function. Also present are alterations in mood, manifested by increased rates of depressive and anxiety symptoms.

Summary 

Patients with overt or subclinical thyroid dysfunction commonly complain of decrements in cognitive function, but studies suggest that such decrements are most likely to be minor or not related to the thyroid dysfunction. More common are mood alterations, which often improve with treatment.