Abstract
Background: Thyroid hormone has important actions in adult brain, and it is well accepted that hypothyroidism is associated with neuropsychiatric symptoms which refer to a spectrum of emotional and cognitive problems and also mood changes. More severe hypothyroidism can mimic melancholic depression and dementia. Subclinical hypothyroidism (SCH) is a condition in which thyroid-stimulating hormone (TSH) value is raised, but FT3 and FT4 values are within normal limit. The prevalence of SCH is 3–7% in general population and as high as 17% in elderly women. A recent study shows people with SCH have impaired working memory.

Aims and Objectives: The present study attempted to find the correlation between anxiety, depression, and executive function with SCH.

Materials and Methods: In this study, anxiety, depression, and level of executive function are being assessed in cases of SCH within a period of 1 year (July 2014–June 2015). Cases were collected from patients attending the Department of Biochemistry for thyroid function tests in North Bengal Medical College and Hospital in that period. Patients of 20–50 years of age group having TSH value 5.5–10 mU/L with FT4 and FT3 within normal reference range (FT4 = 0.8–2.7 ng/dl, FT3-1.4–4.5 pg/ml) were included in the study. Patients already on thyroxin supplementation, with pre-existing psychological illness and substance abuse, with chronic diseases and neurological diseases are excluded from the study.

Results: The extent of anxiety was mild (P < 0.001), whereas depression was moderate (P < 0.07) among the cases of SCH. The executive function was normal in most of the cases. Correlation between anxiety and SCH was found to be statistically significant (P = 0.000), also between depression and SCH (P = 0.027).

Conclusion: It is seen from the study that the extent of anxiety was mild among the SCH in North Bengal Medical College, whereas the extent of depression was moderate among the cases and the executive function was normal in most of the cases. There is a significant correlation between anxiety and SCH and depression and SCH. Anxiety and depression were not significantly correlated with age, sex, and body mass index among the cases of SCH.

Key words: Subclinical Hypothyroidism; Anxiety; Depression; Executive Function; Thyroid-stimulating Hormone