AMNESIA

Amnesia refers to loss of memory and is often the result of a traumatic event. There are two basic types of amnesia: anterograde and retrograde. Retrograde amnesia is a loss of memory that occurs before the time of the event. For example, you forget something that happened before you got hit on the head. Anterograde amnesia is a loss of memory that occurs after the time of the event, such as forgetting something that happened after having surgery.

Contrary to popular opinion, anterograde amnesia is probably more common. Most people with amnesia experience a loss related to specific time periods. The movie image of forgetting everything about your personal past but remembering everything to do with daily functioning is a myth.

Most amnesia is due to physical causes. These include:

a blow to the head
stroke
poisoning
substance abuse
vitamin deficiency
malnutrition and
dementia

Amnesia should always be considered serious enough to call for a full evaluation by a healthcare provider. However, it is common to experience a certain amount of memory loss around a severe injury. For example, many people involved in a severe car accident may experience both types of amnesia. This does not necessarily indicate any severe or lasting damage. Many people experience a certain amount of amnesia after surgery.

A specific type of amnesia is called transient global amnesia, or TGA. TGA is caused by a problem related to decreased blood flow in the brain. It may happen to someone only once or many times. Another type of amnesia is psychogenic amnesia. This is amnesia caused by a psychological trauma. People with this amnesia may forget events around a terrible incident, such as witnessing the violent death of a loved one. Unlike amnesia caused by physical factors, these memories can often be retrieved by psychotherapy or hypnosis. Sometimes the memories return on their own.

Frequent episodes of amnesia can also be related to certain psychological conditions. Amnesia is common for people with one of the dissociative orders. These disorders can be treated, but the first step is accurate diagnosis.

Disclaimer: This content is reviewed periodically and is subject to change as new health information becomes available. The information provided is intended to be informative and educational and is not a replacement for professional medical evaluation, advice, diagnosis or treatment by a healthcare professional.

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