Less basal thyrotropin levels predict antidepressant response in patients with major depression

INTRODUCTION: The close association among thyroid metabolism, mood disorders and behavior has long been known. The role of basal thyroid axis in antidepressant treatment response is less known. OBJECTIVES: The aim of the present study was to study the association of basal serum thyrotropin (TSH) levels, with antidepressant treatment response in major depressive disorder. METHODS: Thirty-one depressed adult outpatients were included. Major depressive episode was diagnosed through the MINI (DSM-IV-TR) interview. Clinical symptomatology and blood samples were assessed at baseline, and at 4- and 8-weeks of either escitalopram or sertraline. Treatment response was defined by an improvement ≥50% in MADRS scores at 4-, and 8-weeks. Basal TSH levels were included in a linear regression model as predictor of treatment response. RESULTS: Twenty-seven patients finished 8-weeks of treatment. Response to treatment was of 74% at 4-weeks, and 63% at 8-weeks of antidepressant treatment. Basal median TSH levels were between normal ranges (M+SD=1.85+1,02 mlU/L). Basal TSH levels not correlated with basal MADRS scores, but with higher MADRS scores at week-4 (r=0,415, p=0,031) and at week-8 (r=0,392, p=0,043). Moreover, less baseline TSH levels trend to be a significant good predictor for treatment response at 4-weeks (R(2)=.116, p=.083); and a good predictor at 8-weeks treatment (R(2)=.147, p=.049). CONCLUSIONS: Baseline TSH levels even within the normal range may play a role in predicting antidepressant response. DISCLOSURE: No significant relationships.