Is Divalproex a Cost Effective Alternative in the Acute and Prophylactic Treatment of Bipolar I Disorder?

Letter to the Editor

Sir: A recent pharmacoeconomic study concluded that divalproex
is a less costly treatment than lithium in the acute and
prophylactic treatment of patients with bipolar I disorder.

Such a decision-analytic study must rest on hard data, and
hard data supporting the prophylactic properties of divalproex
are unavailable. The authors did mention that no controlled
study assessed the prophylactic efficacy of divalproex, and, to
our knowledge, no such study has been published since then.