An open study of triiodothyronine augmentation of selective serotonin reuptake inhibitors in treatment-resistant major depressive disorder.

Objective: In an open trial, we investigated the efficacy of triiodothyronine (T(3)) adjuvant to selective serotonin reuptake inhibitors (SSRIs) in subjects with major depressive disorder (MDD) resistant to SSRI treatment.

Methods: Twenty subjects who met DSM-IV criteria for MDD (mean +/- SD age = 44.3 +/- 10.3 years; 55% [N = 11] women) and had failed to respond to a course of treatment of at least 8 weeks with an SSRI antidepressant were enrolled in a 4-week open-label augmentation treatment with T(3) 50 microg/day. Atypical and melancholic sub-types of MDD were diagnosed using Structured Clinical Interview for DSM-IV Axis I Disorders criteria. We administered the 17-item Hamilton Rating Scale for Depression (HAM-D-17) 4 times during the study (which was conducted between 2001 and 2003).

Results: During T(3) augmentation, the severity of depression decreased from an initial mean +/- SD HAM-D-17 score of 20.5 +/- 3.6 to a final HAM-D-17 score of 14.0 +/- 7.1 (p < .001). Seven subjects (35.0%) were treatment responders (HAM-D-17 reduction >or= 50%), and 6 subjects (30.0%) achieved clinical remission (final HAM-D-17

Conclusions: Triiodothyronine augmentation of SSRIs may be a promising treatment strategy in SSRI-resistant MDD, particularly in subjects with the atypical MDD subtype.