Amnesia is a state of mind wherein months or years of memories suddenly vanish. There are two types of amnesia: organic and functional.
Organic amnesia is caused by damage to the brain brought about by head injuries, severe illness, senility (old age), concussions or violent blows, alcoholism, and stroke.
Functional amnesia is caused by trauma (shocking event or horrifying scene) or stress. Generally, organic amnesia lasts longer than functional amnesia.
The return of memory, assisted by complete rest by a patient and by attempts to establish associations with the past in the patient’s mind, can help in the return of memory.