The use of triiodothyronine (T3) in the treatment of bipolar depression: A review of the literature.
Level 5 - mechanism / opinion, no new human data
Narrative literature review summarizing a heterogeneous mix of mostly uncontrolled and retrospective studies.
PubMed 29331701 · doi:10.1016/j.jad.2017.12.071
What was done
Authors searched Medline, Limo, and ScienceDirect for studies evaluating triiodothyronine (T3) as an acceleration or augmentation strategy in bipolar depression. The review identified seven studies: three open-label studies, one comparative study, two double-blind studies, and one retrospective chart review.
What was found
A total of 353 subjects were included across all studies, with only 194 in prospective trials. The three open studies observed improvement in 56%, 75%, and 79% of patients, the retrospective chart review reported 89% improvement, and the mirror design study reported 66% improvement. In the comparative study, T3 was significantly better than placebo. The only randomized double-blind study found no substantial difference between T3 and placebo. Only two prospective trials analyzed bipolar patients separately.
Why it matters
Adjunctive T3 is often considered for refractory bipolar depression, but current literature consists almost entirely of small, open-label, or retrospective studies without randomized trial support.
Limits
The total evidence base is limited to 353 patients (194 prospective), with only one randomized trial. Included studies had high variability in assessment tools, baseline medications, and treatment-resistance levels, and most did not analyze bipolar patients separately.
Cited by
- partial Functional psychiatry uses T3 to treat conditions like manic depression and schizophrenia due to T3 receptor sites in the brain.