Thyroid-stimulating hormone is associated with differential antidepressant and anti-anhedonic response to ketamine in bipolar depression but not major depressive disorder

Baseline TSH levels were associated with ketamine's antidepressant and anti-anhedonic effects in BD but not MDD. These findings suggest that TSH may serve as a predictive biomarker of response and highlight a potential thyroid-glutamate influence in ketamine's mechanism of action.