Confirming our previous results [4], MDDs with current SBD exhibit HPT axis abnormalities evoking a form of central hypothyroidism consistent with a decreased hypothalamic TRH drive leading to a paucity of releasable TSH (particularly evident in the evening when the TSH circadian pattern approaches its acrophase) and a reduction in the activation of the thyroid gland. The gene discussed is TRH; the disease is Central hypothyroidism.