APA Dictionary of Psychology

a condition characterized by significant cognitive decline in one or more areas of cognitve abilities (e,g,, executive function, learning and memory, social cognition) that interferes with everyday functioning and is not within the context of delirium or explained by another mental disorder. Major neurocognitive disorder was included as a new diagnosis in DSM–5, replacing prior designations of dementia and amnestic disorder, and is also included in DSM-5-TR.