Columns > Published on November 21st, 2013

It's Made Of SCIENCE: Amnesia

Amnesia is the O Fortuna of the literary fiction world. It's a popular, serious theme which has been used so often it borders on parody. We have seen countless iterations of the amnesiac hero. The disorder has been used in storytelling at least as early as the 1600's with Giambattista Basile's The Dove, and continues to make appearances in our books and movies today.

Amnesia is a convenient trope to play with, because world-building becomes the story, rather than introduces it. The amnesiac is as confused by everything as the reader, so the story becomes the unveiling of setting and characters. This information itself is often the climax of the entire story. The concept of losing our memories is a powerful one, because in our memories is the entirety of our lives, our personalities, the relationships that we've built, and the lessons that we've learned. Characters with memory loss are like babies born in adult bodies, with the skills to interact with the world, but no place in it.

So all in all, it's powerful and dramatic and makes for a rather unique type of story that can be difficult to achieve through other mechanisms. But is the traditional portrayal of the symptoms, causes, and treatment of amnesia accurate? Let's take a look.


Because this is SCIENCE, of course there must be a way to break down something you thought was simple into smaller pieces. In this case, there are two broad concepts of memory which are very different, but important to distinguish when discussing amnesia for reasons that will hopefully become clear in a moment.

Declarative memory describes the process by which you recall information through a conscious act. You remember your name, you remember that London is the capital of England, you remember the last few Presidents of the United States. In addition to pure knowledge, declarative memory also covers recollections of your own past experiences, such as smells and emotions. It can also be broken down into episodic memory about our own lives, and semantic memory, which stores factual information.

Procedural memory covers things that you've learned to do, but don't consciously have to recall. For instance, you probably don't need to remember whatever silly game you had to learn to tie your shoes. You probably don't even remember tying your shoes in the morning. You didn't always know how to do it, but now it works unconsciously. Reading is the same way. As a child, you not only had to learn to sound out words and guess what they were, but also remember definitions, grammar, and so forth. Now you're reading Finnegan's Wake and comprehending every word without even thinking about it. Or is that just me?

Anyway, the reason I call this out is because these two types of memory are stored in different parts of the brain. Declarative memory is handled by the neocortex (the thinking part of your brain), while the cerebellum (which controls a lot of your unconscious needs like motor coordination) deals with your procedural memories. We consider it amnesia when problems affect declarative memories rather than procedural, and the reason is simple. While you generally want to avoid damaging your brain if at all possible, the neocortex tends to handle less of your biological needs, and more of what makes you a sentient human being. If you damage your cerebellum, it affects your movement, which isn't really considered a memory problem by laypeople. Considering that the cortex and the cerebellum are on opposite sides of your noggin, an injury that causes damage to both is probably giving you something worse to worry about than memory loss.


Amnesia is known as "dissociative amnesia" in the medical community (didn't I just write about another dissociative disorder recently?).

Retrograde amnesia is almost certainly your default definition when you hear the word "amnesia." The "retrograde" part means "in the past," so this is the kind of amnesia where people lose memories that have happened in the past. An individual may lose specific memories, or more rarely may forget everything about their own identity.

Anterograde amnesia is less popular in fiction, but tends to make for excellent movies like Finding Nemo and Memento (bring up Fifty First Dates at your own peril). This is the type of amnesia that prevents new memory formation. As mentioned earlier, patients with anterograde amnesia can learn new skills, but may not remember that they've learned them (because their declarative memory is affected, not their procedural memory). The problem is in the individual's long-term memory, so while they may remember the last few minutes, everything before then cannot be consciously recalled.

Typically, individuals will present with a little of both anterograde and retrograde amnesia, rather than a pure form of either. Pure amnesia of either form is rare outside of a solely-psychological cause for the memory loss, but it has been known to happen. It can also be kind of difficult to tell exactly what kind of amnesia is occurring if the term is short enough. For instance, do you know whether you remember falling asleep and forget it as soon as you wake up (retrograde), or if you are unable to form memories of the process of falling asleep (anterograde)? Both cases lead you to not remember what it's like to fall asleep, but it's not easy to know exactly which process occurred (or if it was a bit of both).

It's also worth noting that individuals suffering from amnesia will often present with other comorbid psychological disorders, such as post-traumatic stress disorder. This makes sense when you consider the typical causes of amnesia, which are... in the next section. Don't rush me, this is my article.


So let's be straight with each other here. The brain is an absolutely enigmatic organ (zombies have a complex palette). We're the only creatures on the planet with the ability to study our own brains, and yet, we still have so little about it figured out. Memory is even more elusive, because while we have been able to demonstrate that memory can be affected by damage to certain areas of the brain, we can't exactly "see" memory in the brain to know where it's located or how it travels along the neurons. It also doesn't help that the brain has this ability called neuroplasticity, which means that it can sense damage and essentially reroute its neural pathways to continue functioning, sort of like traffic going through alleys and backyards to get around a sinkhole in the road.

The concept of losing our memories is a powerful one, because in our memories is the entirety of our lives, our personalities, the relationships that we've built, and the lessons that we've learned.

Basically what I'm saying is that without knowing much for certain about the mechanisms of memory processing and storage, it's hard for scientists to know exactly what can result in memory problems. But general experience has taught us quite a bit by studying the unfortunate souls who already suffer from amnesia. Let's follow the trend of this article and break this down into a few different categories and see how you can give your poor character amnesia.

Biological causes include naturally-occurring incidents which can result in memory loss. We're talking mainly about disease here, so this will include Alzheimer's disease, encephalitis (inflammation of the brain), stroke or heart attack (which cut off oxygen to the brain), seizures, and so forth. This may be a more certain way of causing brain damage to your character, but it presents some challenges in fiction, considering that these problems cause other side effects that can debilitate your character pretty severely.

Chemical includes causes like alcohol, benzodiazepines, roofies, and other drugs. If you've ever blacked out from drinking too much, you probably know that chemically-induced amnesia tends to cover fairly short periods of time (the time in which the chemical is actually affecting the brain), so it may seem a little silly if your character loses their identity after a night of hard partying. On the other hand, if you need a surgical level of precision in your character's forgetfulness, this will be one of the "safest" and easiest ways to do it.

Physical causes are those which physically damage the brain from the outside. These are really going to be the least precise ways of giving your character amnesia, because again, we aren't sure exactly what kind or severity of damage will definitely result in memory loss. Remember that this is brain damage, and the overused trope of someone getting hit in the head with a pipe and suffering no ill effects other than memory loss is going stale. Unless you want your character also being paralyzed or losing control of their bladder for no apparent reason, I'd advise against leaning too heavily on blunt force trauma for your amnesia needs.

Psychological causes generally refer to severe psychological trauma. This can result in mental coping mechanisms where the brain shuts out the painful memory altogether. The memory may be stored in the long-term memory just fine, but the brain refuses to go retrieve it. This is seen commonly with rape victims, who may not remember their attacker, or in abused children. In general, the memory loss will be specific to the traumatic event, and won't cascade into wiping out other areas of the memory. Note that psychological issues are very specific to the individual, and an event which leaves one character severely traumatized may be easy for another to shrug off completely.


Treatment options depend entirely upon the individual case of amnesia. In many cases, the option is to just wait for the problem to right itself, which the majority of incidents seem to do. Honestly, you can have your character re-read books he doesn't remember owning, or hide his own Easter eggs, and just wait it out. The undramatic truth is that amnesia doesn't always require going on a vision quest to regain one's identity.

That being said, some cases of amnesia are so debilitating and/or long-lasting that active treatment is required. There are currently no drugs out there that treat amnesia, so unless the memory loss is caused by an underlying biological condition such as Wernicke-Korsakoff syndrome, therapy offers the only real treatment options. This can sometimes take the form of re-exposing the individual to their own memories, or even replacing their memories with new ones to help them function. Often, therapy will also help individuals learn coping mechanisms to deal with memory loss, like the use of schedules, notes, and hopefully rad tattoos.

Oh, and I feel I should point out that hitting someone on the head to cure their memory loss isn't any more likely to fix them than is hitting your broken car with a sledgehammer to make it work better. Chances are that you're going to make things much, much worse. And anyway, curing your character's amnesia with a bump on the noggin is a pretty lazy way out of that problem, isn't it?

Bottom Line

If you've read closely, you'll probably notice that a case can be made for the typical media portrayal of amnesia as being possible in the real world, and you'd be right. It is entirely possible that a secret agent ninja can get shot in the head, survive with no memory of who he is, and go on an incredible journey to reclaim his identity. It's also possible that such a wound wouldn't have done any bit of damage besides the amnesia.

It's possible. But laughably unlikely.

In my own purely-opinionated view, the typical portrayal of amnesia affects characters far too conveniently, where authors cherry-pick the symptoms of a mental disorder that work for them. Sure, it's fiction, but portraying amnesiacs this way is getting a bit old, and you'll have to do something pretty interesting with them in order to stand out from the mass of tropey amnesia stories out there. Why not try an amnesiac villain? Or perhaps have your character not have any idea that he has amnesia? Maybe you can have someone who has amnesia, but doesn't let anyone know, and just tries to play it off as we all do when we don't recognize someone who clearly knows us.

This theme has made for a few great stories, and a lot of formulaic, boring ones. Aim to make your amnesiac character unforgettable, or risk getting lost in the fog.

Do you have an idea for my next science-themed article? I'm taking suggestions! Drop me some topics in the comments, and if I like it, and feel that I either understand or can research it well enough to explain it, your idea can be the next IMOS article. Also, feel free to call me out if you spot an error anywhere; I'd rather have a perfect article than a reputation for being perfect.

About the author

Nathan Scalia earned a BA degree in psychology and considered medical school long enough to realize that he missed reading real books. He then went on to earn a Master's in Library Science and is currently working in a school library. He has written several new articles and columns for LitReactor, served for a time as the site's Community Manager, and can be found in the Writer's Workshop with some frequency.

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