Objective: To compare the efficacy and tolerability of lithium versus quetiapine for the treatment of manic or mixed episodes in youths with early course bipolar I disorder. Methods: Six-week, randomized, double-blind clinical trial of lithium versus quetiapine for the treatment of adolescents with acute manic/mixed episode. Target dose of quetiapine dose was adjusted to a target dose of 400-600 mg and target serum level for lithium was 1.0-1.2 mEq/L. Primary outcome measure was baseline-to-endpoint change in the Young Mania Rating Scale (YMRS). Secondary outcomes were treatment response (50% or more decrease from baseline in YMRS score) and remission (YMRS score ≤12, Children's Depression Rating Scale-Revised [CDRS-R] total score ≤28 and Clinical Global Impression Bipolar Severity Scale [CGI-BP-S] overall score of ≤3, respectively). Results: A total of 109 patients were randomized (quetiapine = 58 and lithium = 51). Participants in the quetiapine treatment group showed a significantly greater reduction in YMRS score than those in the lithium group (-11.0 vs. -13.2; p < 0.001; effect size 0.39). Response rate was 72% in the quetiapine group and 49% in the lithium group (p = 0.012); no differences in remission rates between groups were observed. Most frequent side effects for lithium were headaches (60.8%), nausea (39.2%), somnolence (27.5%), and tremor (27.5%); for quetiapine somnolence (63.8%), headaches (55.2%), tremor (36.2%), and dizziness (36.2%) were evidenced. Participants receiving quetiapine experienced more somnolence (p < 0.001), dizziness (p < 0.05), and weight gain (p < 0.05). Conclusions: Treatment with both lithium and quetiapine led to clinical improvement. Most study participants in this study experienced a clinical response; however, less than half of the participants in this study achieved symptomatic remission. The head-to-head comparison of both treatment groups showed quetiapine was associated with a statistically significant greater rate of response and overall symptom reduction compared with lithium. Trial registration: clinicaltrials.gov NCT00893581.
Keywords: bipolar disorder; early-course; lithium; mania; quetiapine.