Delirium: The importance of subsyndromal states

This article reviews scientific studies that have examined subsyndromal delirium (SSD). The main purpose of the article is to address the question of whether these findings support the notion of delirium as a spectrum disorder, or whether they support the notion of subsyndromal states of delirium as qualitatively different from the Diagnostic and Statistical Manual of Mental Disorders-based diagnosis. This article ends by proposing a framework that incorporates the notion of SSD and the interactions among risk factors, stress, and pathophysiological factors.