Self-reported adherence to treatment with mood stabilizers, plasma levels, and psychiatric hospitalization.

Abstract

The authors explored the relationship of adherence to treatment with mood stabilizers (lithium, carbamazepine, and sodium valproate) and plasma levels of these drugs to future psychiatric hospitalizations. They prospectively followed 98 patients with mood disorders who were prescribed mood stabilizers. These patients participated in an initial interview and completed a questionnaire regarding their adherence to the medications. Data on their plasma levels of these drugs were taken from assays done in the 3 months before the interview. Six of the 98 patients were not classified as to medication adherence or plasma levels. Twenty-nine (32%) of the remaining patients reported partial adherence to the medication regimen, and 33 (36%) had an index plasma level that was suboptimal. At 18 months, rates of admission to a psychiatric hospital were significantly higher in the 16 partially adherent patients with subtherapeutic plasma levels (N=13, 81%) than in the 46 adherent patients with therapeutic plasma levels (N=4, 9%). However, hospital admission was also more likely in partially adherent patients with therapeutic plasma levels than in adherent patients with subtherapeutic plasma levels. Adherence to medication regimens may be a proxy measure of other healthy behaviors.