Adjuvant thiamine improved standard treatment in patients with major depressive disorder: results from a randomized, double-blind, and placebo-controlled clinical trial.

Given that antidepressants (ADs) work slowly, there is interest in means to accelerate their therapeutic effect and to reduce side effects. In this regard, thiamine (vitamin B) is attracting growing interest. Thiamine is an essential nutrient, while thiamine deficiency leads to a broad variety of disorders including irritability and symptoms of depression.