Association between thyroid functions, cognition, and functional connectivity of the brain in early-course schizophrenia: A preliminary study

Background: The functional outcome of the debilitating mental illness schizophrenia (SZ) has an integral role in cognition. The thyroid hormone has a vital role in the developmental stages and functioning of the human brain. Aim: This study aimed to evaluate the relationship between thyroid functions, cognition, and functional imaging of the brain in persons with SZ. Materials and Methods: Sixty SZ (Diagnostic and Statistical Manual (DSM-5)) persons, aged 18–50 years of both genders, were recruited in this cross-sectional observational study. Positive and Negative Syndrome Scale (PANSS) and Trail Making Tests (TMTs) A and B were administered to all patients. To assess the level of thyroid hormone, a test was conducted. Functional connectivity of the brain was assessed using resting-state functional magnetic resonance imaging (rs-fMRI). Data analysis was performed by descriptive and analytical statistical methods. FSL version 5.9 (FMRIB's) software was used for analyses of fMRI neuroimages. Results: There were no significant differences between the two populations on sociodemographic factors. The average value for thyroid-stimulating hormone (TSH) in the hypothyroid group (n = 12) and the euthyroid group (n = 47) was 8.38 mIU/l and 2.44 mIU/l, respectively. The average time in seconds for TMT-A and TMT-B was 87.27 and 218.27 in the hypothyroid group and 97.07 and 293.27 in the euthyroid group, respectively. Similarly, in the sample matched on age, gender, and age at onset of illness, there were no significant differences in demographic and clinical factors and resting-state network (RSN) between the hypothyroid (N = 10) and euthyroid (N = 10) groups. Conclusion: No differences were found in the functional brain network between the hypothyroid and euthyroid groups as the study sample did not include clinically hypothyroid persons with SZ.