This review article on the maneuver of lithium addition to the pharmac
ological regimen of patients with antidepressant resistant depression
describes the methodology and results of the controlled and open relev
ant studies published to date, states the hypothesized mechanisms of a
ction, and discusses some of the methodological problems that limit th
e usefulness of previous research efforts. It finally outlines possibl
e areas of interest for further research.