Amnesia

Amnesia is a what doctors call a loss or disturbance of memory. In simple terms, it is a loss of memory, that is to say, a person cannot remember certain things. There are two "main types":

• Anteretrograde amnesia: Short term memory is not transferred to long-term memory any more: This means the person is unable to create new memories.
• Retrograde amnesia: The person can no longer recall certain events that happened in the past. This has nothing to do with simply forgetting things.

Some of the more common amnesias include:

• Caused by a trauma, for example a head injury; called post-traumatic amnesia.
• Dissociative amnesia: Here the cause is psychological, and usually not related to physical damage in the brain. This includes
  • Repressed memory (where it is not possible to remember a specific event) - The memory is usually still there, but the person blocks access to it; Stressful events such as being raped may lead to Dissociative amnesia
  • Childhood amnesia - the inability of adults to remember certain parts of their childhood.
• Drug (usually alcohol)-induced blackout - anteretrograde amnesia, affecting the immediate past

Amnesia can be permanent, or it can be temporary. Damage to the brain, or the use of certain drugs can cause amnesia. Some of these drugs are sedatives. Another well known cause for amnesia can be drinking too much alcohol. Those kinds of causes are called organic, because they can been directly seen. Other causes cannot directly be seen, they are called functional. Rather they are psychological in their nature. People may want to shield off a traumatic event they witnessed, for example.