This narrative review examines the declining use of lithium in the treatment of bipolar disorder, despite its proven efficacy. Lithium is the most effective treatment for bipolar disorder, yet its prescription has decreased globally over recent decades. The review highlights the evidence for lithium's acute and prophylactic effects, discusses challenges such as side effects and long-term risks, and provides examples of specialized care models that have successfully increased lithium use to 70% of patients with bipolar disorder. The conclusion emphasizes the need for organizational changes and specialized care to systematically increase lithium use as the first-line treatment for bipolar disorder.This narrative review examines the declining use of lithium in the treatment of bipolar disorder, despite its proven efficacy. Lithium is the most effective treatment for bipolar disorder, yet its prescription has decreased globally over recent decades. The review highlights the evidence for lithium's acute and prophylactic effects, discusses challenges such as side effects and long-term risks, and provides examples of specialized care models that have successfully increased lithium use to 70% of patients with bipolar disorder. The conclusion emphasizes the need for organizational changes and specialized care to systematically increase lithium use as the first-line treatment for bipolar disorder.