Alzheimer disease (AD) is one of the most common neurodegenerative disorders (prevalence boosts from 0.2% in patients aged 55-65 up to 27% in patients aged 85+ years. Clinical manifestations of psychiatric disorders accompanying hypo- and hyper-thyroid function can mimic cognitive impairment.

Our study aimed at studying the relationship between thyroid pathology, anxiety disorder and Alzheimer disease (AD).

Our longitudinal, prospective research followed 49 patients with thyroid disorders (aged 50-85 years, 93.5 females); 63.3% (n = 31) had coexisting dementia and thyroid disease while 36.7% (n = 18) were dementia-cleared (10 had mild cognitive impairment (MCI) and 8 - anxiety and/or depression); we cross/analyzed control (n = 18) and target (n = 31) groups.

In the target group, 64.5% (n = 20) had hypothyroidism, 22.6% (n = 7) had euthyroid function and 12.9% (n = 4) had hyperthyroidism. The prevalence of anxiety and depression was higher in the hypothyroidism + dementia group (55.5%, n = 11) than in the hypothyroidism-only group (44.4%, n = 8). Most controls (77.8%, n = 14) had hypothyroidism while 22% (n = 4) had normal thyroid function.

Anxiety disorder had a greater prevalence both in the group with dementia + thyroid disease and in the MCI group. Hypothyroidism was the dominant thyroid disorder in both groups. The early diagnostic and treatment of thyroid disease is expected to improve prognosis and evolution of future cognitive disorders (MCI & AD).