Some people experience events so traumatic to them that in order to cope they have to create a new self to retreat into, or even replace their old self with a new one effectively destroying it. Some people snap and enter a fugue state, which is characterized by complete memory loss brought on by immense stress. The individual simply stops knowing who they are and often end up in locations far from home with different names and no functioning memory of their life.
Perhaps the most intriguing dissociative disorder is Dissociative Identity Disorder (DID). There is no commonly accepted definition of DID, but the general diagnosis requires the presence of at least two additional personalities within a person’s mind. The public’s fascination with the disorder reaches back as far as 1886 with the publication of Robert Louis Stevenson’s The Strange Case of Dr. Jekyll and Mr. Hyde. The notion that a mind can split into multiple personalities is a popular subject in modern media: Fight Club, Primal Fear and Identity all address the topic. We all seem to agree that everyone has a good side and a bad side without the convenience of explaining the different characteristics as completely different individuals within someones psyche, but that’s the basis of DID, especially when used as a criminal defense.
In the late 1970’s and young man named Billy Milligan was arrested in connection with a series of crimes surrounding Ohio State University including armed robbery and 4 accounts of rape; the tip was anonymously phoned in. Billy had what seemed like a typical story: abused as a child, constantly drifted around, repeatedly in trouble with the law, couldn’t hold a job or maintain a stable life. Things got really weird once Billy was evaluated by a psychologists. The police noted during the questionings that Billy would seemingly change accents and postures at various points. The accounts provided by the victims were also a bit strange. Differing accents and mannerisms were noted, even though each victim identified Billy as the culprit. It turned out Billy was housing 24 different personalities in his head. A Slavic personality named Ragen claimed responsibility for the armed robbery, stating he did it in order to feed his family. Two of Billy’s personalities were female. In fact it was Adelena, a 19 year old lesbian, who claimed responsibility for the rapes in an effort to feel close to someone. David, a 9 year old boy, was the personality that called the police and made the tip. This was known because the phone used to make the tip was in Billy’s room with the police phone number written beside it. Billy was found not guilty by reason of insanity; he committed the crimes but could not be held responsible for them. Consequently, this created the giant increase in criminal defense teams trying to plea insanity due to DID. This didn’t work for the notorious Hillside Strangler Ken Bianchi who claimed his alter ego Steven Walker was responsible. Bianchi was unaware of the required diagnosis of at least two other alter egos, and conveniently another personality manifested in hypnosis sessions after this fact was conveyed to him (he was also a psychology student, which was another knock against his defense).
The tricky thing about DID is that while there are a lot of discussions about the topic in textbooks, it is probably one of the most controversial subjects in all of psychology. There isn’t a common definition of it, let alone many studies backing it up. Much of the psychology community debates whether or not it exists at all. DID popped up in the 1800’s as psychology as a field began to form and laid dormant until the 1970’s when movies, television and books started giving it more attention. This corresponds with the sudden increase in diagnosed patients. Unfortunately these cases always came from the same few professionals. DID also seemed to be relatively confined to North America, another knock against its credibility. All things considered, DID is often considered as role-playing taken to an extreme, because our media portrays a lot of DIDThat’s not to say there isn’t any evidence for it, or that people who present with DID are intentionally faking it. DID patients have demonstrated memory loss that varies from personality to personality; each personality may have access to different memories than the other personalities. Brain imaging studies have revealed that patients with DID manifest different patterns of brain activity when different personalities take control. As tantalizing as that might seem it’s not as conclusive as you’d think because we can alter our brain activity simply by thinking about various things or letting emotions well up and affect our thoughts.
The most intriguing evidence for DID as Bruce Hood points out is a strange case of a German woman who, after being diagnosed blind for 15 years, suddenly began to regain her eyesight after undergoing therapy. It started off with only a few of her personalities regaining vision while the others remained blind. In order to establish if she was faking or not, her doctors took electrical measurements of her visual cortex. When a sighted personality was dominant, the electrical activity in her visual cortex was the same as anyone else’s who can see. When a blind personality was in control, her visual cortex as completely shut off. Whatever part of her brain that was generating multiple personalities was also able to completely shut off an entire section of her brain.
For additional reading, I recommend:
Hood, Bruce. The Self Illusion: How the Social Brain Creates Identity. Oxford University Press, 2012.