I Forget... What Can Cause My Characters Amnesia?

Amnesia is pretty fascinating for a writer, don’t you think? Whether you’re writing a mystery, an epic fantasy, a historical drama or anything in between or beyond, the possibilities are endless—particularly if you know your stuff about amnesia.

If you read the previous Psychology & Storycraft post, you’ll know that there’s not just one type of amnesia (though popular media tends to give the impression otherwise). Keep that knowledge in mind over the next couple of posts as we dig into some of the ways your characters could sustain memory loss and how you can use them to great effect in your novels.

Amnesia can have physical or psychological causes, ranging from bumps on the head to dissociative episodes. Knowing the different causes of amnesia and how they come about can help you select the most appropriate one for your character, should a period of amnesia be called for in the story.

Physical Causes of Amnesia

Head Injury: Brain Trauma and Concussions

The first thing that comes to my mind when thinking of causes of amnesia is a blow to the head. When a blow is strong enough to cause a concussion without penetrating the skull, it can cause post-traumatic amnesia. It’s a plot device that’s been used time and time again by authors and screenwriters, but what actually happens when you get a crack to the skull strong enough to cause amnesia?

Firstly, a coma. After a severe blow to the head, you could be unconscious for anything from seconds to weeks. The more severe the blow, the longer the coma tends to be. After waking up, there’s a period of confusion, which is followed by retrograde amnesia for events just before the blow and anterograde amnesia for those just after. (Can’t remember what retrograde and anterograde amnesia are? Find out here.)

In other words, memories of the events that led up to the blow to the head will be inaccessible and anything that happened during the period of confusion after waking from the coma will be difficult to remember too. You might remember isolated events from these amnesic periods (known as ‘islands of memory’), but otherwise the loss of these memories is usually permanent.

Korsakoff’s Syndrome

It’s common knowledge that drinking excessive amounts of alcohol can produce some memory loss, but Korsakoff’s syndrome, a memory disorder, isn’t so well known. It’s found in chronic alcoholics, but also in those with severe malnutrition, and features episodes of both anterograde and retrograde amnesia.

In the early stages of Korsakoff’s syndrome, anterograde amnesia is particularly pronounced in episodic memories, meaning that explicit recollections of recent events are impaired. For example, if you suffered from Korsakoff’s syndrome, you might forget speaking with someone the previous day or what you ate for lunch earlier.

In the later stages of Korsakoff’s syndrome, you experience progressively worse retrograde amnesia, which can wipe out memories all the way back to childhood. Implicit memory remains intact, though, so you can still remember how to do things like make a cup of tea or tie your shoe laces.

Alzheimer’s Disease

Another cause of amnesia is Alzheimer’s disease, a form of dementia found predominately in over 65s, featuring progressively severe memory loss.

In the very early stages of the disease, there’s mild deterioration in memory—for example, you might find it difficult to remember words or things you learnt recently and could struggle forming new memories, as with anterograde amnesia. As Alzheimer’s disease progresses, memory worsens, with long term memories being increasingly affected. Personality changes, deterioration in speech and, eventually, loss of movement control can also occur as the disease enters its later stages. You can find out more about the individual stages of Alzheimer’s disease here.

Psychological Causes of Amnesia

Dissociative Amnesia

Caused by an incredibly traumatic and stressful event, this type of amnesia involves the loss of some or all of the memories about yourself and can last from several hours to several months (or longer). During that time, the memories of your past, your personality, your identity—gone. There’s a lack of anterograde amnesia though, so you’re perfectly capable of forming new memories.

Fugue State

Along with the symptoms of dissociative amnesia, if you’re in a fugue state, the sudden need to escape the stressful event that caused your amnesia takes hold, leading to purposeful travel away from home. Like dissociative amnesia, fugue states can last anywhere from hours to months, and are often paired with the creation of a new identity.

Because no other functions are really affected, it can be very difficult to spot you if you’re in a fugue state. When you come out of it, there’s understandable confusion as memories of what you did during the fugue state may be forgotten. Experiencing more than one fugue state is rare, but when it does happen, it’s usually a result of a dissociative identity disorder.