Delirium Superimposed on Dementia

Background: Delirium and dementia are highly interrelated. Delirium superimposed on dementia can alter the course of an underlying cognitive impairment, with dramatic worsening of the trajectory of cognitive decline, resulting in more rapid progression of functional losses. This review seeks to identify challenges in the recognition and management of delirium superimposed on dementia and highlight strategies to improve patient care. It also aims to examine its pathophysiology, risk factors, diagnosis and clinical outcomes. Methods: This narrative review discusses the current knowledge on close interaction between delirium and dementia. We searched the following databases: PubMed, Google Scholar, Web of Science, and AgeLine. A comprehensive literature search was conducted for studies published between 1970 and 2026. Results: Dementia is a known risk factor for delirium. The literature suggests that cerebral vulnerability in patients with dementia may predispose them to the development of delirium. This review gives a general overview of delirium superimposed on dementia. It starts with a general discussion of the nature of the interrelationship between delirium and dementia. This is followed by research studies in this field, including pathophysiological relations between delirium and dementia, and the effects of delirium on dementia progression. Finally, we show different methods to manage delirium in patients with dementia. The review identifies the following key findings: (1) the coexistence of dementia and delirium presents significant diagnostic challenge because of overlapping symptoms; (2) delirium superimposed on dementia is associated with poorer clinical outcomes than either condition alone, including accelerated cognitive and functional decline; (3) prevention remains the most effective management strategy; and (4) multicomponent non-pharmacological interventions, carried out by a multidisciplinary team, have demonstrated benefits in reducing delirium incidence. Conclusions: Delirium superimposed on dementia is frequently under-recognized. Early diagnosis and management of delirium superimposed on dementia can be challenging. More effort is needed to better standardize and optimize symptom assessment. Multicomponent preventive measures should be applied to decrease the risk of this condition. The aim of the treatment is to identify and treat the underlying cause. It is essential to improve caregivers’ knowledge about this syndrome to improve healthcare quality.