Early Improvement with Lithium in Classic Mania Predicts Later Response

Abstract

Background: Lithium is a first line approach for acute episodes and maintenance treatment of bipolar disorder (BD). Despite lithium ́s clinical efficacy in treating BD mania, studies evaluating early improvement and subsequent treatment response are sparse. This study investigated whether early improvement (within one week of treatment) to lithium monotherapy predicted later response and remission in individuals with BD mania. Methods: BD-I patients (n=46) experiencing a manic episode received lithium monotherapy for four weeks (initial dose: 600mg/day, adjusted to therapeutic levels); individuals experiencing a mixed episode, rapid cyclers, previous non-responders to lithium, and those with current drug abuse/dependence were excluded. Symptoms were rated using the Young Mania Rating Scale (YMRS) weekly. Results: Thirty-three percent of the total sample responded to lithium within the first week of treatment, as assessed by a ≥50% decrease from baseline YMRS scores; 63% responded by study endpoint. In addition, 39% of the total sample (18/46) showed early improvement, defined as an at least 20% decrease in YMRS scores after one week of treatment. In this group, 79% responded to lithium by study endpoint. Meanwhile, among those showing less than 20% improvement at Week 1, only 23% responded to lithium by study endpoint. Conclusions: Early improvement in response to lithium monotherapy in subjects with BD during a manic episode predicted later response and remission. The findings provide a valuable clinical tool for early identification of those patients most likely to benefit from lithium in clinical practice.