The combination of triiodothyronine (T3) and sertraline is not superior to sertraline monotherapy in the treatment of major depressive disorder

Objective: To determine whether the combination of triiodothyronine (T3) plus sertraline at treatment initiation confers greater antidepressant efficacy than sertraline plus placebo in patients with major depressive disorder.

Method: Eight-week, double blind, randomized placebo controlled clinical trial of 153 adult outpatients between 18 and 60 years of age, with DSM-IV defined major depressive disorder. Patients were treated with sertraline flexibly adjusted for tolerability and in a double blind fashion with placebo or T3 (25 μg/day in week 1 and increasing to 50 μg/day in week 2). Response was defined categorically as 50% reduction and total score less than 15 in 21-item Hamilton Rating Scale for Depression (HRSD-21) at week 8 and remission as HRSD-21 less than 8.

Results: There was no difference between treatment groups at final assessment; 65% of placebo and 61.8% of T3 treated subjects achieved response and 50.6% of placebo and 40.8% of T3 treated patients achieved remission. The mean daily dose at final assessment of sertraline and T3, respectively was 144.7 mg (± 48.7 mg) and 48.2 μg (± 7 μg). Median time to response did not differ between treatment groups. Baseline thyroid function tests did not predict response to sertraline treatment or T3 augmentation.

Conclusions: These results do not support the routine use of T3 to enhance or accelerate onset of antidepressant response in patients with major depressive disorder.