The relation between thyroid dysregulation and impaired cognition/behaviour: An integrative review

Abstract

Prevalence of cognitive impairment and dementia substantially increases with ageing, especially in the oldest old population. 1 Thyroid disorders are also prevalent in the elderly population, with the prevalence of hypo-and hyperthyroidism reaching 30% and 10% respectively. 2,3 It has been long noted that disorders of thyroid function can lead to cognitive impairment. Therefore, thyroid dysfunctions are important and potentially modifiable risk factors of cognitive impairment in the older individuals. 4 Thyroid dysfunctions can be categorised based on the serum levels of thyroid hormones (thyroxine [T4] and triiodothyronine [T3]) and thyroid-stimulating hormone (TSH) level as: overt hypothyroidism: decreased T4/T3 levels and increased TSH; overt hyperthyroidism: increased T4/T3 and decreased TSH; subclinical hypothyroidism: normal T4/T3 levels with increased TSH; and subclinical hyperthyroidism: normal T4/T3 levels and decreased TSH level. 4 The association of hypo-or hyperthyroidism with cognition and behaviour has been investigated in many experimental animal studies, 5-7 and also in human observational and experimental studies, as well as clinical trials. 8-11 The objectives of this review are: • To provide a summary of the spectrum of cognitive and behavioural impairments related to thyroid disorders

Higher CSF/serum free‐T4 ratio is associated with improvement of quality of life during treatment with L‐thyroxine

“…Primary hypothyroidism (PH) is one of the most common autoimmune diseases 1 affecting up to 4% of the adult population in Sweden 2 . There is a five‐fold higher prevalence in females, and PH is widely included in screening protocols for symptoms such as fatigue and depressive mood 3–7 . PH is associated with a broad array of clinical symptoms as thyroid hormones affect virtually all the cells in our body.…”

“…2 There is a five-fold higher prevalence in females, and PH is widely included in screening protocols for symptoms such as fatigue and depressive mood. [3][4][5][6][7] PH is associated with a broad array of clinical symptoms as thyroid hormones affect virtually all the cells in our body. The symptoms include muscle pain, decreased sweating, peripheral edema and CNS symptoms such as fatigue, depressive state, and cognitive deficits.…”

Thyroid Disorders and Development of Cognitive Impairment: A Review Study

“…Patients with endocrine disorders may experience neurologic diseases [6]. Among endocrine disorders, thyroid disorders have been known as risk factors for progressive cognitive impairment development, either in the form of hyperthyroidism or hypothyroidism [7]. The present article tries to review the relationship between thyroid disorders with dementia and cognitive impairments.…”

Cognitive decline in mid-life: Changes in memory and cognition related to hypothyroidism

“…Although there are many common physical and psychological symptoms associated with hypothyroidism, those affected often report declines in cognitive functions, including problems with memory or slower thinking, which can lead to problems with everyday tasks, such as driving (Smith et al, 2015). Additionally, thyroid hormonal dysregulation may be a modifiable risk factor for future cognitive impairment and dementia (Eslami-Amirabadi and Sajjadi, 2021). Thus, further investigation into the specific areas of cognition affected in individuals with hypothyroidism is warranted.…”

“…Hypothyroidism can cause a wide range of neurocognitive problems, which are often referred to as “brain fog.” These problems typically manifest into deficits in general intelligence (Crown, 1949; Eslami-Amirabadi and Sajjadi, 2021); executive functioning (Haggerty Jj et al, 1986); and problems with attention, concentration, and language (Mennemeier et al, 1993; Whybrow et al, 1969). Previous research has found that hypothyroidism can also cause deficits in short-term memory (Osterweil et al, 1992) and long-term memory (Aghili et al, 2012; Botella-Carretero et al, 2003).…”