Thyroid Disorders in Mental Patients
Thyroid Disorders in Mental Patients
Samuels reviewed recent population-based studies on the effects of untreated hypothyroidism and hyperthyroidism on cognitive function in adult populations. Patients with overt or subclinical thyroid alterations showed only minor cognitive dysfunction that may not have been directly related to thyroid function. The most commonly affected cognitive domains related to thyroid dysfunction are working memory and executive function. Among mental symptoms, alterations in mood are most often reported.
In a double-blind, randomized, cross-over trial, Samuels et al. treated hypothyroid patients with two doses of T4. The larger dose led to subclinical thyrotoxicosis, whereas the smaller dose led only to euthyroidism. The larger dose caused improvement in mood and learning, and positive effects were related to an increase in free T3 concentrations.
In an elderly population, it was reported that increased thyrotropin concentrations, suggesting diminished thyroid function, were associated with worsened cognitive performance assessed by the Mini-Mental State Examination (MMSE). In those without overt thyroid disease, high normal FT4 concentrations two years later were associated with a loss in MMSE performance. The authors concluded that T4 can generate oxidative stress and damage neurons with increasing age.
In the Framingham study, both low and high baseline thyrotropin concentrations after 12 years of follow-up were associated with increased risk of Alzheimer's disease in women but not in men. This suggests that long lasting hyperthyroidism as well as long lasting hypothyroidism may result in cognitive decline, at least in elderly women.
Cognitive Function in Adults
Samuels reviewed recent population-based studies on the effects of untreated hypothyroidism and hyperthyroidism on cognitive function in adult populations. Patients with overt or subclinical thyroid alterations showed only minor cognitive dysfunction that may not have been directly related to thyroid function. The most commonly affected cognitive domains related to thyroid dysfunction are working memory and executive function. Among mental symptoms, alterations in mood are most often reported.
In a double-blind, randomized, cross-over trial, Samuels et al. treated hypothyroid patients with two doses of T4. The larger dose led to subclinical thyrotoxicosis, whereas the smaller dose led only to euthyroidism. The larger dose caused improvement in mood and learning, and positive effects were related to an increase in free T3 concentrations.
In an elderly population, it was reported that increased thyrotropin concentrations, suggesting diminished thyroid function, were associated with worsened cognitive performance assessed by the Mini-Mental State Examination (MMSE). In those without overt thyroid disease, high normal FT4 concentrations two years later were associated with a loss in MMSE performance. The authors concluded that T4 can generate oxidative stress and damage neurons with increasing age.
In the Framingham study, both low and high baseline thyrotropin concentrations after 12 years of follow-up were associated with increased risk of Alzheimer's disease in women but not in men. This suggests that long lasting hyperthyroidism as well as long lasting hypothyroidism may result in cognitive decline, at least in elderly women.