Delirium disorder: Integrating delirium and acute encephalopathy

As the US population ages and with no definitive delirium treatments on the horizon, the delirium epidemic is on course to expand over the coming decades. Recognizing the import of this condition, a recent position statement from 10 medical societies-among whom the American Academy of Neurology was represented-issued recommendations on preferred nomenclature of delirium and acute encephalopathy: it concluded by preferring both terms. Urgently needed is an integrated model that addresses the near-total segregation of these separate bodies of literature, ideally one that offers an interdisciplinary framework to bring these 2 terms and those who use them together.

We review the historical forces that have led these terms to diverge and consider the unique benefits of each approach as well as their liabilities when considered in isolation. We then explore the potential implications of integrating these concepts and propose a hybrid model to capitalize on the strengths of both the model of delirium and that of acute encephalopathy.

The model we propose-delirium disorder-builds on the recommendations of this recent position statement and provides a unifying framework designed to have clinical utility and interdisciplinary appeal. It also broadens the translational landscape by identifying 4 distinct treatment targets: underlying causes, procognitive factors, delirium (phenotype alone), and neurophysiologic targets.

This person-centered model aims to integrate delirium and acute encephalopathy within a single framework and shared nomenclature. It is hoped that this model aids in harmonizing research efforts and advancing clinical practice.