The most common cause of organic amnestic syndrome is
organic amnesia and the amnestic syndrome. .The amnestic syndrome is characterized by disorientation paicularly in time, impairment of immediate recall, loss of recent memory, retroactive loss of remote memory of varying extent and a tendency to confabulation. Ref Harrison20th edition pg 2776
Alzheimer's disease
Concussion
Hypoxia
Vitamin deficiency
C.N.S