What disorder is characterized by a rapid loss of cognitive function and is often reversible?

Delirium is recognized as a disorder characterized by a rapid onset of confusion and cognitive dysfunction, which can fluctuate throughout the day. It is usually triggered by an underlying medical condition, substance intoxication or withdrawal, infections, or electrolyte imbalances, among other factors. One of the distinguishing features of delirium is its potential reversibility; when the underlying cause is identified and treated, cognitive function can often return to baseline levels.

This differs from conditions like dementia, which typically have a more gradual onset and are degenerative in nature, meaning they usually indicate a progressive decline in cognitive abilities. Alzheimer's disease, a type of dementia, also displays a chronic trajectory and is not considered reversible. Pseudodementia can mimic dementia—often seen in depression—but it typically does not present with the same rapid cognitive fluctuations found in delirium. Understanding these differences is crucial for proper diagnosis and management in clinical practice.