“Gold Standard, but...”: Exploring the Evidence-Practice Gap in Lithium Prescribing for Bipolar Disorder — A Qualitative Study of UK Psychiatrists

Abstract Background Lithium remains the most evidence-based prophylactic treatment for bipolar disorder, yet its use has declined steadily across most developed health systems despite consistent guideline endorsement. Cross-sectional surveys have documented this evidence-practice gap but cannot explain how clinicians reconcile their stated endorsement of lithium with their actual prescribing behaviour. This qualitative study explores how psychiatrists in the English National Health Services (NHS) understand, justify, and navigate decisions about lithium prescribing. Methods Twenty psychiatrists across two large NHS mental health trusts (13 consultants, 3 senior trainees, 2 core trainees, 2 speciality doctors) took part in semi-structured one-to-one interviews conducted online. Transcripts were analysed using Braun and Clarke’s reflexive thematic analysis, with coding performed inductively in NVivo 15. Results Six interlocking themes were identified: (1) a persistent gap between declarative endorsement of lithium’s evidence base and its delayed use in practice; (2) patient-selection heuristics that progressively narrow who is considered “suitable”; (3) practitioner, patient, and systemic barriers to prescribing; (4) marked inconsistency in the thresholds clinicians apply to lithium levels and renal risk; (5) facilitators, including confidence in managing side effects and structured monitoring support; and (6) clinician-generated suggestions for closing the gap, centred on training and earlier exposure. Conclusions NHS psychiatrists universally endorse lithium’s evidence base, but a self-reinforcing cycle of selective patient suitability, eroded confidence and systemic friction keeps it as a late-line rather than first-line choice. The barriers are attitudinal, experiential and systemic rather than rooted in unfamiliarity with the evidence, pointing to specific, modifiable levers for change.