Also Known As: Confusion, DIsorientation, Delirium
"Acute Mental Confusion" is used interchangeably with Delirium in International Statistical Classification of Diseases and Related Health Problems and Medical Subject Headings to describe a pathological degree in which it usually refers to loss of orientation (ability to place oneself correctly in the world by time, location, and/or personal identity) sometimes accompanied by disordered consciousness and often memory (ability to correctly recall previous events or learn new material). Confusion as such is not synonymous with inability to focus attention, although severe inability to focus attention can cause, or greatly contribute to, confusion. Together, confusion and inability to focus attention (both of which affect judgment) are the twin symptoms of a loss or lack of normal brain function (mentation). The milder degrees of confusion as pathological symptoms are relative to previous function. Thus (for example) a mathematician confused about manipulation of simple fractions may be showing pathology which would not be diagnosable in a person without training in this area. Thus, as with the case of delirium, the minor degrees of pathological confusion cannot be diagnosed without knowledge of a person's "baseline", or normal, level of mental functioning.
Confusion may result from drug side effects.
Confusion may result from a relatively sudden brain dysfunction. Acute confusion is often called delirium (also called acute confusional state), although delirium also includes a broader array of disorders than confusion, e.g. inability to focus attention and various impairments in awareness and temporal and spatial orientation.
Confusion may also result from chronic organic brain pathologies such as dementia. In either case, confusion is usually associated with some degree of loss of ability to focus attention, but (as noted) the association is not invariable, especially for lesser degrees of impairment.