Amnesia

Amnesia is when you have serious memory loss. It can be a symptom of other conditions or happen by itself.

Amnesia comes from ancient Greek and means, “forgetfulness.” But it’s more than that. Forgetfulness is misplacing your keys or not remembering to do something while running errands. Amnesia involves being unable to remember significant events or details from your life.

Are there different types of amnesia?

There are two main forms of amnesia. Retrograde amnesia is when you can’t recall memories from your past. Anterograde amnesia is when you can’t form new memories but can still remember things from before you developed this amnesia.

Other forms of amnesia include:

• Post-traumatic amnesia. This is amnesia you develop after an injury. It can involve multiple forms of amnesia.
• Transient global amnesia. This is a short-lived condition that involves both anterograde and retrograde amnesia. It almost always lasts less than 24 hours.
• Infantile amnesia. This is amnesia from when you were a baby. Almost everyone has this. Remembering things from infancy is rare.
• Dissociative amnesia. This is amnesia that happens because of a mental health-related cause. Traumatic events, abuse and other severe sources of psychological distress can cause it. Experts suspect it’s a defense mechanism your brain uses to protect you from what you experience.

How common is amnesia?

Amnesia is uncommon on its own. But it’s a very common symptom of certain conditions. These conditions usually involve brain damage or activity disruptions. An example is Alzheimer’s disease, a major cause of amnesia. About 24 million people worldwide have Alzheimer’s, which accounts for millions of people with amnesia. And there are dozens of other possible causes.