Improvement of Depression in a Patient with Hypothyroidism and Deiodinase Polymorphism with LT3 Therapy

We report a 54-year-old man with treatment-resistant depression (TRD) and hypothyroidism who responded to LT3/LT4 combination, rather than LT4 alone. He was able to discontinue all antidepressant medications eventually. Interestingly, the patient has a DIO2 polymorphism.