Dissociative amnesia is one of a group of conditions called dissociative disorders. Dissociative disorders are mental illnesses that involve disruptions or breakdowns of memory, consciousness, awareness, identity, and/or perception. When one or more of these functions is disrupted, symptoms can result. These symptoms can interfere with a person's general functioning, including social and work activities, and relationships.
Dissociative amnesia occurs when a person blocks out certain information, usually associated with a stressful or traumatic event, leaving him or her unable to remember important personal information. With this disorder, the degree of memory loss goes beyond normal forgetfulness and includes gaps in memory for long periods of time or of memories involving the traumatic event.
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Dissociative amnesia is not the same as simple amnesia, which involves a loss of information from memory, usually as the result of disease or injury to the brain. With dissociative amnesia, the memories still exist but are deeply buried within the person's mind and cannot be recalled. However, the memories might resurface on their own or after being triggered by something in the person's surroundings.
What Causes Dissociative Amnesia?
Dissociative amnesia has been linked to overwhelming stress, which might be the result of traumatic events -- such as war, abuse, accidents, or disasters -- that the person has experienced or witnessed. There also might be a genetic link to the development of dissociative disorders, including dissociative amnesia, because people with these disorders sometimes have close relatives who have had similar conditions.
Who Develops Dissociative Amnesia?
Dissociative amnesia is more common in women than in men. The frequency of dissociative amnesia tends to increase during stressful or traumatic periods, such as during wartime or after a natural disaster.
What Are the Symptoms of Dissociative Amnesia?
The primary symptom of dissociative amnesia is the sudden inability to remember past experiences or personal information. Some people with this disorder also might appear confused and suffer from depression and/or anxiety.
How Is Dissociative Amnesia Diagnosed?
If symptoms of dissociative amnesia are present, the doctor will begin an evaluation by performing a complete medical history and physical exam. Although there are no lab tests to specifically diagnose dissociative disorders, the doctor might use various diagnostic tests, such as as neuroimaging, electroencephalograms (EEGs), or blood tests, to rule out neurological or other illnesses or medication side effects as the cause of the symptoms. Certain conditions, including brain diseases, head injuries, drug and alcohol intoxication, and sleep deprivation, can lead to symptoms similar to those of dissociative disorders, including amnesia.
If no physical illness is found, the person might be referred to a psychiatrist or psychologist, health care professionals who are specially trained to diagnose and treat mental illnesses. Psychiatrists and psychologists use specially designed interview and assessment tools to evaluate a person for a dissociative disorder.