DEFINITION

• Concurrent disturbances of both consciousness and cognition resulting in disturbances of attention (and additional memory, visuospatial and/or executive dysfunction) often accompanied by changes in psychomotor behavior, perception, emotion, and sleep-wake cycle.
• Duration is variable, but onset is often abrupt, usually over the course of hours to days, and ranging in severity.
  • Can persist for weeks to months (specifier of persistent in DSM-5).
• Delirium is a clinical syndrome indicating underlying pathology.
  • It is not a disease unto itself.
• Delirium is classified under the neurocognitive disorders (NCDs) section of the Diagnostic and Statistical Manual of Mental Disorders, 5th Edition (DSM-5)[1].