Serum Lithium Monitoring, Short-Term Outcomes, and Treatment Barriers in Bipolar Disorder: A Real-World Study

To characterize serum lithium monitoring, clinician-recorded short-term outcomes, and treatment barriers in a clinically selected outpatient cohort of patients with bipolar disorder that was enriched for suicide risk.

We retrospectively reviewed consecutive routine-care records from a specialist mood-disorders clinic between January 2024 and March 2025. The monitoring dataset comprised 188 patients and 562 valid serum lithium measurements. The outcome dataset comprised 124 patient-level records from initial or follow-up encounters, and a separate implementation dataset contained 13 patients with documented discontinuation or non-initiation. The serum lithium value closest to the clinical outcome assessment was used in exploratory analyses.

Among monitored patients, 124/188 (66.0%) had at least two measurements. Median serum lithium concentration was 0.62 mmol/L (interquartile range 0.50-0.84), and 18/562 measurements (3.2%) were >1.2 mmol/L. Clinician-recorded remission was documented in 72/124 outcome records (58.1%) and any improvement in 114/124 (91.9%). Any improvement was 90.0%, 96.1%, and 81.5% in the <0.4, 0.4-<0.8, and ≥0.8 mmol/L groups, respectively (exploratory unadjusted P=0.053). Remission did not differ across groups (P=0.952), and the continuous serum lithium value was not associated with remission (odds ratio per 0.1 mmol/L, 1.01; 95% confidence interval 0.86-1.18). Documented barriers included adverse effects, testing or logistical burden, toxicity concerns, and poor palatability.

A single routine-care serum lithium concentration recorded near a clinical assessment was not associated with clinician-recorded remission. The analysis did not evaluate longitudinal exposure or confirmed steady-state trough concentrations, and improvement during comprehensive care cannot be attributed to lithium alone. These findings support an integrated lithium-care pathway that combines interpretable monitoring, accessible testing, early management of adverse effects, clear toxicity education, and suicide-specific safety planning.