Amnesia may be caused by Thiamin deficiency (by causing Wernicke encephalopathy or Korsakoff psychosis) in patients with chronic alcohol abuse or severe undernutrition Traumatic brain injury Seizures Global brain anoxia or ischemia Encephalitis Embolic occlusion at the top of the basilar artery, causing ischemia in the anterior medial temporal lobes Degenerative dementias such as Alzheimer disease Various drug intoxications (eg, chronic solvent sniffing, amphotericin B or lithium toxicity) Hypothalamic tumors Psychologic trauma or stress Wernicke-Korsakoff syndrome is a form of amnesia that combines Wernicke encephalopathy and Korsakoff psychosis.