Delirium
Delirium is a medical term used to describe an acute (i.e. relatively recent) decline in attention-focus, perception, and cognition. Because it represents a change in cognitive function, the diagnosis cannot be made without knowledge of the affected person’s baseline level of cognitive function.
Without careful assessment, delirium can easily be confused with a number of psychiatric disorders because many of the signs and symptoms are conditions present in dementia, depression, and psychosis.[1]
Delirium is probably the single most common acute disorder affecting adults in general hospitals. It affects 10-20% of all hospitalized adults, and 30-40% of elderly hospitalized patients.
Delirium itself is not a disease, but rather a clinical syndrome (a set of symptoms), which result from an underlying disease or new problem with mentation. Like its components (inability to focus attention and various impairments in awareness and temporal and spacial orientation), delirium is simply the common symptomatic manifestation of early brain or mental dysfunction (for any reason).