Relationship between thyroid-stimulating hormone, BDNF levels, and hippocampal volume in antipsychotic-naïve first-episode psychosis patients

Abstract

IntroductionThyroid hormones play an essential role in hippocampal development, a key structure in psychosis. However, the role of these hormones in first-episode psychosis (FEP) has received limited attention. It has been hypothesized that thyroid hormones could cause morphological modifications in the hippocampal structure through the upregulation of brain-derived neurotrophic factor (BDNF). In this study, we primarily aimed to determine the relationship between thyroid-stimulating hormone (TSH) levels, peripheral BDNF levels, and hippocampal volume in antipsychotic-naïve FEP patients. We also aimed to determine whether TSH levels were associated with clinical symptomatology.Materials and methodsA total of 50 antipsychotic-naïve FEP patients were included in the study. At baseline, we collected fasting blood samples and registered sociodemographic and clinical variables (substance use, DUP, PANSS, GAF, and CDSS). Structural T1 MRI was performed at baseline to quantify brain volumes. No control group was used for this study.ResultsOf the 50 patients, more than one-third (36%) presented alterations in TSH levels, mainly elevated levels (32% of patients). The TSH levels were inversely correlated with both peripheral BDNF and hippocampal volume. On the multivariate analysis, the model that best predicted the relative hippocampal volume was a single variable model (TSH levels). No significant association was observed between TSH levels and clinical symptomatology.DiscussionThese results suggest that thyroid hormones could have a neuroprotective effect on the hippocampus in FEP patients, possibly through their effect by increasing BDNF concentrations, which could attenuate brain injury and neuroinflammation. Nevertheless, thyroid hormones could also affect hippocampal volume through other pathways.

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“…In individuals with depression, one study revealed a correlation between elevated TSH levels, decreased serum BDNF levels, and a lower rise in BDNF during antidepressant treatment ( 41 ). A more recent study examining 50 patients undergoing their first episode of psychosis showed that high TSH levels were associated with low peripheral BDNF and reduced hippocampal volume, suggesting a potential neuroprotective effect of THs on the hippocampus ( 42 ).…”

Is the acquired hypothyroidism a risk factor for developing psychiatric disorders?

“…Using magnetic resonance imaging (MRI) in patients with untreated acquired hypothyroidism, a reduction in hippocampal volume has been observed ( 141 ), as well as a reduction specifically in the granular and molecular layers of the hippocampus ( 142 ). It has been proposed that the volume reduction correlates with a decrease in peripheral BDNF levels ( 143 ). In addition, using positron emission tomography (PET), it has been shown that hippocampal glucose utilization is reduced in hypothyroid patients ( 144 ).…”