Major disorders of memory deserve our attention and these include anterograde, amnesia reetrograde amnesia, psycho-genic amnesia and dementia among others.

a) Anterograde amnnesia

Anterograde amnesia can be caused by brain tumors; severe nutritional deficiencies. In addition, hard blows to the head can also cause anterograde amnesia. However persons with anterograde amnesia perform badly on long term declarative memory tasks but perform well as normal individuals on procedural memory tasks.

b) Retrograde amnesia

This is a memory disorder characterized by an inability to retrieve old long term memories generally for a specific period of time extending back from the beginning of the disorder.

Retrograde amnesia can be caused by seizures, brain damage of various sorts, or highly stressful events. However it generally occurs along with anterograde amnesia, because both anterograde and retrograde amnesia are experienced by individuals with Korsak off’s syndrome caused by excessive abuse of alcohol, because of their extreme degree of memory in confabulation i.e. when they cannot remember something that is needed to complete a statement they make.

c) Psycho-genic amnesia

Some people suddenly lose their memory only to recover it month or even years later

Such persons are victims of psycho-genic amnesia. This is a sudden disruption of memory that seems to take place in response to unbearable space. Such a stress seems to split one’s memory (dissociate) from conscious awareness.