Multiple Personalities Disorder: Symptoms & Summary

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  • 0:05 Dissociative Identity Disorder
  • 1:04 Diagnosis
  • 3:58 Causes & Treatment
  • 4:55 Controversy
  • 6:30 Lesson Summary
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Lesson Transcript
Instructor: Natalie Boyd

Natalie is a teacher and holds an MA in English Education and is in progress on her PhD in psychology.

In this lesson, you will learn how difficult life is for someone suffering from the rare and serious mental disorder once known as multiple personality disorder. We'll also explore its symptoms, causes and treatments, and why there's a controversy over it in the psychological community.

Dissociative Identity Disorder

Even if they haven't read it, most people have heard of Dr. Jekyll and Mr. Hyde. In Robert Louis Stevenson's 19th century story, the main character is both the benevolent Dr. Jekyll and the evil Mr. Hyde. But could that happen in real life?

Multiple personality disorder, which is more often called by its clinical name, Dissociative Identity Disorder, or DID for short, is a severe and complicated mental illness in which an individual seems to display two or more distinct personalities. The personalities, often called alters, operate completely independent of each other and from the individual's main personality (sometimes called the host) in behavior, in thoughts and in styles. Let's look closer at DID, including diagnosis, causes and treatment of the disorder, as well as controversy within the psychological community that has been sparked by the disorder.


Imagine that you're a psychologist and Dr. Jekyll comes to visit you. He's concerned because he doesn't remember long periods of his life. Sometimes, he seems to black out for days at a time! Not only that, but some people he's never met swear they know him well, but they call him by different names: Mr. Hyde, Captain Porter, and others.

You think Dr. Jekyll might have dissociative identity disorder. In order to diagnose him, you go through a checklist of symptoms of the disorder:

1. Two or more personalities.

DID patients have at least two, and often many more, distinct personalities that reside within them. Each personality has its own history, thoughts and way of viewing the world.

In Dr. Jekyll's case, he is the kind-hearted doctor, but he's also the evil Mr. Hyde. Not only that, but he has another personality, Captain Porter, that is a man who fights for justice and good but does so violently. Of course, in Stevenson's story, there were only two personalities, Jekyll and Hyde, but in dissociative identity disorder, there are often more than just those two. In our example, all three personalities are very different, and all three are unique personalities, so Dr. Jekyll meets this criterion.

2. At least two personalities regularly take over the person's actions.

A person with DID might seem to be two totally different people if you meet them at different times. That's because, in a way, they are. They have different personalities controlling them at different times.

Remember how Dr. Jekyll meets people who swear they know him as Mr. Hyde or Captain Porter? This is because when they met him, one of those personalities had taken over and was controlling Jekyll's behaviors.

3. Severe loss of personal memory.

Patients with DID often have large amounts of time that they don't remember. They might have blackouts lasting days at a time, or not be able to recall what they did on their 10th birthday, for example.

Dr. Jekyll has blackouts that last for long periods of time, and he can't remember anything about his life during that time. These gaps in his memory are when another personality has control of him. Mr. Hyde, for example, might be able to remember what happened to Dr. Jekyll last Tuesday, even if Dr. Jekyll himself can't.

4. There's not another explanation for the symptoms.

Sometimes, people blackout from alcohol and drug use, and there are other medical and psychological reasons that might explain the symptoms of DID. But Dr. Jekyll is healthy and doesn't drink or do drugs, so there's no other explanation for his symptoms.

Since he meets all four criteria, we can diagnose Jekyll with DID.

Causes and Treatment

Individuals suffering from DID are not born with separate personalities. The division of personalities happens as a result of some sort of serious childhood trauma, possibly physical or sexual abuse, emotional abuse, or severe neglect. In each case, the child is sadly unable to flee from or stop the trauma and must bear it for a length of time.

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