Changes in Use of Valproate and Other Mood Stabilizers for Patients With Schizophrenia From 1994 to 1998

OBJECTIVE: The study describes changes over time in the adjunctive use of valproate and other mood stabilizers—lithium, carbamazepine, and gabapentin—among hospitalized psychiatric patients with a diagnosis of schizophrenia. METHODS: For each calendar year from 1994 through 1998, data were drawn from a database containing clinical and drug prescription information for every inpatient in the adult civil facilities of the New York State Office of Mental Health. RESULTS: In 1994 a total of 26.2 percent of inpatients diagnosed as having schizophrenia received a mood stabilizer, compared with 43.4 percent in 1998. In 1994 lithium was the most commonly prescribed mood stabilizer, for 13.2 percent of patients, followed by valproate, for 12.3 percent. In 1998 valproate was the most commonly prescribed, for 35 percent of patients, followed by lithium, for 11.3 percent. On average, patients received valproate for about two-thirds of their hospital stay, at a mean dose of 1,520 mg per day. CONCLUSIONS: The adjunctive use of valproate nearly tripled from 1994 to 1998 among patients with a diagnosis of schizophrenia. Valproate has become the most commonly prescribed mood stabilizer for this population, despite the paucity of evidence in the literature for efficacy in this use. Controlled clinical trials are needed to examine the adjunctive use of mood stabilizers, in particular valproate, among patients with schizophrenia.