A mental disorder characterized by impairment of memory. The person is unable to learn new information and to recall previously learned knowledge. It is termed transient if impairment lasts for 1 month or less or chronic if impairment lasts for more than 1 month. Amnestic disorder may be substance induced or due to a general medical condition.
Any of a group of disorders marked by memory disturbance that is due either to the direct physiological effects of a general medical condition or to the persistent effects of a drug, toxin, or similar substance. Affected patients are unable to recall previously learned information or past events. Social or occupational functioning is significantly impaired.