Amnesia is memory loss that may be caused by a head injury or stroke, substance abuse, or a severe emotional event, such as combat or a motor vehicle accident. Depending upon the cause, amnesia may be temporary or it may be a permanent condition.
Amnesia can involve complete loss of memory of one or more of the following:
The cause determines whether the condition comes on slowly or suddenly. Memory problems that come on gradually may be a part of ongoing mental decline (dementia). Total global amnesia is a type of unexplained amnesia that begins suddenly.
Treatment options and results of treatment of amnesia depend on the cause of lost memory.
WebMD Medical Reference from Healthwise