The Relationship Between Thyroid Status, Cortisol Level, Cognition And Neuropsychiatric Symptoms In Patients With Alzheimer Disease

Abstract

Objective: Growing evidence suggests an association between alterations in thyroid function and cortisol level and the pathogenesis and progression of Alzheimer disease (AD). The aim of this study was to investigate whether these hormones are related to the cognitive and neuropsychiatric manifestations in the patients with AD.Methods: This was a cross-sectional, case control study. Cortisol level and thyroid status were evaluated in 40 outpatients with mild to moderate AD and 20 normal controls, and cognitive and neuropsychiatric assessments were performed using the Cognitive Ability Screening Instrument (CASI), Neuropsychiatric Inventory, and Geriatric Depression Scale. Results:The patients had worse cognitive function and lower free triiodothyronine (FT3) level than the controls. Those with aberrant motor behavior had a lower FT3 level, and those with dysphoria had a higher cortisol level than those without these symptoms. The patients with a higher level of FT3 also had higher concentration and abstract thinking/judgment scores on the CASI, and those with a higher level of cortisol were associated with a decline in global cognition. Conclusion:Our results indicate a possible association between thyroid hormones and neuropsychiatric manifestations as well as cognitive function in euthyroid patients with AD, and suggest the potential efficacy of adjunctive T3 treatment in these patients. We hypothesize that patients with dysphoria subjectively experience more stress. Further studies are needed to elucidate whether this would increase the risk of depression or exacerbate cognitive function, and to investigate whether a non-pharmacological approach can relieve dysphoria symptoms according to the psychological attachment theory.

Higher FT4 or TSH below the normal range are associated with increased risk of dementia: a meta-analysis of 11 studies

“…After carefully scanning the titles and abstracts, 39 articles that were potentially eligible for inclusion were retrieved. After reading the full texts, 28 articles were excluded for the following reasons: nine studies were not cohort or case-control studies 18 19 20 21 22 23 24 25 26 ; 13 lacked usable data 13 14 17 27 28 29 30 31 32 33 34 35 36 ; four had different study purposes 37 38 39 40 ; one did not perform FT4 and TSH measurements 41 ; and one was a replicate study with a shorter follow-up 42 than that by de Jong et al 10 ( Fig. 1 ).…”

Down syndrome: the prevalence of Alzheimer’s disease and the role of thyroid hormone

“…It has been observed that in TD in adults, particularly in hypothyroidism, there are deficits in cognitive functions that are reversible with hormone replacement (DE SOUZA et al, 2016;ZHANG et al, 2012). However, magnetic resonance imaging studies correlate hyperthyroidism with decreased hippocampus and amygdala volumes and the onset of dementia (DE JONG et al, 2006), while other studies have associated prolonged use of T4 with the onset of AD, once TH can regulate the generation of APP isoforms (HARPER; ROE, 2010).…”

The effects of thyroid hormones on memory impairment and Alzheimer's disease

“…The thyroid function has a central role in both neurodevelopment process and neurodegenerative processes. It is suggested in recent years that the thyroid function is linked to the AD; it has been proposed that the thyroid dysfunction enhances the risk of AD by a direct harmful effect of thyroxine discharge on cholinergic neurons; however, whether the neuropathological mechanism of altered thyrotropin levels happens before or after the beginning of AD is unclear (Zhang, Du, Wang, & Cheng, 2012). Treatment with THs can remarkably improve cognition and emotional indices in patients (Bunevicius, 2009).…”