Late-onset Bipolar Disorder and Its Limits With Major Neurocognitive Disorder: A Narrative Review

Manic and manic-like presentations in older adults pose a recurring diagnostic challenge. A first or late manic syndrome may reflect primary late-onset bipolar disorder, but it may equally signal a dementia-related neuropsychiatric syndrome, delirium, or a secondary medical, medication-induced, or vascular cause. Because these possibilities differ in workup, treatment, and prognosis, and because their cross-sectional presentations are often indistinguishable, accurate differentiation relies on longitudinal course, collateral history, and targeted cognitive and neuroimaging assessments, in addition to a deliberate search for secondary etiologies to the patient's symptoms. This review synthesizes the literature on late-onset bipolar disorder, its overlap with major neurocognitive disorders (notably the behavioral variant of frontotemporal dementia), and a practical approach to distinguishing them, while also summarizing current guidance on the pharmacological management of bipolar disorder in later life.