Despite methodological flaws that limit conclusions, a considerable da
tabase documents the efficacy of triiodothyronine (T-3) as an augmenta
tion strategy for response to various classes of antidepressants. One
study suggests that T-3 and lithium are of comparable efficacy in anti
depressant nonresponders. No clear biochemical or clinical predictors
of preferential response to T-3 have been found. The role of T-3 augme
ntation requires further evaluation, especially with regard to dose an
d duration.