Who responds to prophylactic lithium therapy?

The search for predictors of outcome has not been particularly rewarding, and the use of lithium remains empirical: a trial of lithium is the most powerful predictor of outcome. However, lithium is a highly specific treatment for bipolar disorder. In non-bipolar affective disorder, factors of interest are correlates of bipolar disorder: mood-congruent psychotic features, retarded-endogenous profile, cyclothymic personality, positive family history of bipolar illness, periodicity, and normality between episodes of illness.