Now, we're going to turn to a different sort of disorder. The set of disorders known as dissociative disorders. Dissociation is literally a dissociation of yourself from your memory. You forget things. You become unaware of some aspect of your identity or your history. You're unable to remember certain things that happened or certain ways in which you were. Now, some amount of dissociation is normal. You could forget things, obviously, but also in experiences with drugs, with alcohol, with a lack of sleep, you can have something which is akin to a dissociative disorder. But the disorders, of course, are far more serious than that and go beyond temporary, and there are three types of disorders; Dissociative Amnesia, Dissociative Fugue and Dissociative Identity disorders. In Dissociative Amnesia, it's also known as psychogenic amnesia, its just memory loss. You lose part of your memory and it's typically selective. You might know who you are, you might know most of your past. Though, in some cases it could be global. You could lose all of your memory. It's a sort of Hollywood loss of memory where you say, who am I, I have no idea where did I come from. Often this happens after a traumatic event, after some sort of terrible event, like a disaster where you see everybody around you die. Often in criminal situations, say when people are charged with murder, many of them claim to have no memory of what happened and this could be because of the trauma of the event. It could be because people tend to lie under these situations and they aren't describing things accurately. It could also be because in a lot of crimes, drugs and alcohol are involved and this could lead to some sort of Dissociative Amnesia. A second type of dissociative disorder is Dissociative Fugue, also known as psychogenic fugue, and it's just like Dissociative Amnesia. A global sort where you lose all your memory. Except you travel, you leave your home, you go to some other place, you develop a new identity with no recollection of your former life, and when you're gone, when you're living this other identity, this is known as a fugue state. Then, when the fugue state wears off, you're previous identity comes back. You're back to where you were and you might lose all of your memory of where you went and what you did during your fugue state. As you can imagine, this is a very rare disorder and it's quite fascinating. The third sort of dissociative disorder is Dissociative Identity Disorder, and if you didn't hear about it from that name, you've heard of the expression Multiple Personality Disorder. The idea is that person has two or more distinct personalities that are manifested at different times. There are famous cases of the Sibyl, Trudy Chase, Eve. It's been used as a criminal defense including by the Hillside Strangler, mass murder from way back, and it's definitely the stuff of fiction. The phenomena of it begins at around childhood before the age of 10. Most people who are diagnosed with this disorder are women. In most reports, some sort of terrible torture or sexual abuse as children and show signs of post-traumatic stress disorder. So, one way to think about it is that all of this abuse early on leads to the creation of an alternative self, a splitting. But then again, many people who are horribly abused don't develop Dissociative Identity Disorder. Then, so you can tell a similar story that you've seen with regard to anxiety disorders and depression and schizophrenia, where there's a predisposition towards dissociation. Then some sort of series of negative events causes this predisposition to blow up into full-blown disorder. But what I'll end by pointing out is that this is extremely controversial. So, a recent survey suggests that less than a quarter of psychiatrists believe there really is such a thing as associative identity disorders and the statistics are interesting. It used to be that these were extremely rare and then in the 80s they exploded, particularly in the United States where thousands upon thousands of cases were reported. Many of them were reported by the same therapist or some therapists that seem to specialize in finding cases of Dissociative Identity Disorder, and so several really interesting questions arise. One is, is Dissociative Identity Disorder the product of therapy itself, where well-meaning therapist often get patients to reenact or play act in different voices experiences that have happened to them, and could this cause Dissociative Identity Disorder to emerge in a patient who otherwise wouldn't have had one. A second question, which is explored by philosophers like Dan Dennett, is to what extent is Dissociative Identity Disorder, to what extent it exists an extreme version of normal psychology. So, I'm one person when I'm with my wife, I'm another person when I'm with my colleagues and I'm yet another person when I'm with my parents. My personality is a little bit different. I talk a bit differently, maybe I act a bit differently, and in some vague sense, you can call this different personalities. What one wonders is, the extremes of Dissociative Identity Disorder, again, assuming that this is a real phenomenon, may just be an extreme version of the sort of splitting we undergo in everyday life, and I think this is interesting because it's yet another example of how the study of abnormal psychology, of psychopathology, can tell us something about everyday life. The study of mood disorders and anxiety disorders can tell us about our sadness and our anxiety even for people who don't have psychological issues, and perhaps the dissociative disorders could tell us a little bit about everyday dissociation.
