The prophylactic efficacy of lithium--transient or persistent?

It has been reported recently that the prophylactic efficacy of lithium is a transient phenomenon in many patients. Other studies suggest sustained efficacy against affective recurrences for many years. As this issue is of major therapeutic relevance, published literature considering changes in lithium efficacy over time has been reviewed. The present review includes a critical evaluation of the data and the methodology which yielded these controversial results. Considering the published data discussed in this review, the balance of evidence does not indicate a general loss of lithium efficacy in the prophylaxis of major affective disorders. A supposed persistence of the prophylactic effects in general does not, however, exclude the reappearance of affective recurrences after years of successful treatment in individual cases. Possible reasons for this phenomenon are discussed.