Variability of erythrocyte and serum lithium levels correlates with therapist treatment adherence efforts and maintenance treatment outcome

Abstract

This study investigated the relationship between psychotherapeutic interventions and pharmacologic measures of pharmacotherapy treatment adherence in patients with bipolar I disorder, as well as the relationship between these measures and treatment outcome. Subjects were participating in an ongoing maintenance treatment study. Audiotaped therapy sessions were rated for frequency of psychotherapeutic interventions related to pharmacotherapy treatment adherence. Pharmacologic measures of medication adherence were compared to the tape ratings as well as to treatment outcome. Variability in log erythrocyte (RBC) lithium-a marker of probable nonadherence to the pharmacotherapy regimen-for individual patients correlated significantly with treatment adherence interventions scale ratings. This marker of nonadherence was significantly related to maintenance treatment outcome, as was variability of the serum lithium level/dose (L/D) ratio; however, no relationship was found between treatment adherence interventions scale ratings and outcome.