Simons, J.S. and Graham, K.S. (2000). In G. Fink (Ed.) Encyclopedia of Stress (pp. 176-178). Academic Press, San Diego.

The term amnesia refers to a partial or total loss of memory and can be due to organic brain damage and/or some forms of psychological stress. The loss of memory can affect events or experiences occurring either subsequent to the onset of the disorder (anterograde amnesia) or those that took place prior to its appearance (retrograde amnesia). Furthermore, while amnesia most often occurs for personal autobiographical events (episodic memory), some patients also show a loss of semantic memory, our factual knowledge about the world.