Cost-Effectiveness of Divalproex Versus Lithium

Letter to the Editor

Sir: We read with interest the recent application by Keck et
al. of pharmacoeconomic analysis to the treatment of bipolar
disorder. Their study suggested that divalproex was more costeffective
in treating mixed and rapid cycling manic states, that
lithium was more cost-effective in treating classic mania, and
that divalproex was more cost-effective when mixed, rapid
cycling, and classic mania were combined. Like Keck et al.,
we noted the sensitivity of the model to assumptions about
the length of stay (LOS) for divalproex versus lithium.