Aged 29, Karen Overhill was diagnosed with Multiple Personality Disorder. In one of the most intriguing and disturbing cases of its kind, her psychiatrist helped her identify 17 distinct personalities - the result of abuse she'd suffered at the hands of her family. Here, Karen tells her story - and how she found a cure.
On New Year's Eve 1989, I took a trip to Las Vegas with my husband and some friends, leaving our two children at home. Initially, I had gone to bed early feeling unwell, but throughout the evening I then found myself in different parts of the casino and couldn't work out how I got there.
When my husband finally caught up with me, I had $2,500 in my handbag. I'd started with $25. I had to make excuses about where I'd been and why I wasn't in our room - because I simply had no idea how it had happened.
There had been many other similar episodes in my life around that time. One day, I left the house to go shopping for food; but then I "awoke" in a department store to find myself buying my son a hat. I don't really remember making the decision not to go grocery shopping; nor do I know how I got to the store.
Sometimes I'd pick up a novel and discover the bookmark had moved - yet I couldn't remember reading the chapter. Once, I found a knife under my pillow that I couldn't explain.
After the birth of my second child, I began to lose more time and the occurrences left me almost suicidal. Crazy as it must sound, I could not remember marrying or making love to my husband. Nor could I remember anything about my life between the ages of six and 10.
That's why, when I was 29, I went to visit psychiatrist Richard Baer in Chicago. Until that point, I'd always tried to cover up my memory lapses. Dr Baer told me that my "dissociative episodes" could be a way my mind had found to cope with the pain of having been sexually abused by men in my family when I was young.
During my weekly therapy sessions, he suggested I keep notes about the times I found myself in unusual situations. After one Friday night I wrote: "It's 2am and I don't know where I am or how I got here. I don't know what city I'm in. There are no homes; it seems deserted. I don't know what to do. Should I ask for help, or just keep driving until something seems familiar?
"I can't call my husband. He wouldn't understand. I am alone and scared. I'm at a petrol station and there's a lady inside. I'll ask her.
"The lady was very helpful and now I know where I am. We will get home OK."
The fact that I had used the word "we" in my note - although I was definitely alone that night - combined with other information I had already given him, made Dr Baer wonder for the first time if I might have multiple personality disorder (MPD).
He thought that when I was losing time, I might not simply be disassociating with myself, but possibly switching to another personality. A few months later, I was faced with something that would confirm his suspicions.
When I went along for my weekly session, Dr Baer presented me with a letter he had received in the post. Written in a child's hand, it said: "Dear Doctor Baer, My name is Claire. I am 7 years old. I live inside Karen. I listen to you all the time. I want to talk to you but I don't know how."
The return address on the back of the envelope was mine, and although I didn't remember writing the letter and it was written in a child's hand, I knew instinctively it had come from me. I was so shocked, I thought I was going to faint.
For a while I was terrified that Dr Baer - the only man I'd been able to trust - would disown me for being too disturbed, but instead he carefully explained what he now believed.
He told me I had been suffering from MPD, and that research suggested childhood sexual abuse was the most common cause of the condition. He explained that if a person lives with severe, persistent abuse, they sometimes create alternative personalities to cope.
He also explained that it was common for MPD patients to try to hide their symptoms because they feared being labelled as "crazy", and that sometimes an alternate personality could come forward through - among other means - a letter to the therapist.
I realised the letter was a real sign that some part of me finally wanted this out in the open.
After the revelation of "Claire's" letter, it was as though a switch had been flipped. Suddenly, I started to become more aware of other personalities inside me - especially in the evenings and at night. I could almost sit back and watch myself function.
Even routine things such as cooking dinner, housework, or driving the children to school seemed unfamiliar to me much of the time because they were being carried out by other parts of me. I knew I'd done them a thousand times, but I felt like I'd never really done them at all.
At night, I could hear different voices in my head discussing the events of the day - events I could not even remember. Bizarre though it sounds, it seemed to be a way for all these different personalities to catch up with each other.
I began trying to identify the different voices I could hear, and came up with a list that I gave to Dr Baer.
They included four children under ten (three girls and a boy), two teenage girls (Julie and Sandy), a 21-year-old woman, myself, a man and a woman aged 34 (Holdon and Katherine) and another very angry man.
This list really helped to clarify things. I now knew there are at least 11 distinct personalities within me. They had names, ages, unique and separate personality traits, and their own individual histories.
I even started to "see" what they were doing and how they were behaving - but it was distressing and exhausting switching personalities all the time.
I had to rely on one personality - a 30-something male - to drive, for example. If he was otherwise engaged, "we" (the personalities and I) couldn't get anywhere.
Around this time, I would bump into people who claimed to know me, but I didn't recognise them at all. I could only assume that they had a friendship with another side of my character.
By the spring of 1994, I could stand the chaos no longer, and Dr Baer felt I was ready to try to tackle my condition with hypnotherapy - a recognised treatment for MPD. Under hypnosis, I was able to identify my 11 alternate characters and find out more about them.
Over time, six more personalities started to emerge through letters they wrote to my therapist and via our hypnotherapy sessions, making a total of 17. Each one appeared to have been formed to help me deal with specific, difficult aspects of my life and experience.
There was Jensen, for example, an 11-year-old boy, who was "born" in 1971 when I was 12 years old and was raped by my grandmother's brother.
I'd never told anyone about the abuse that I'd suffered for fear that my father would kill me - as he had threatened. Jensen fought back against the abuse and tried to bind my breasts flat to help me appear more masculine. He especially hated older men.
Then there was Juliann - 15 years old and very energetic, who didn't tend to worry about anything. She was disorganised and promiscuous, and tended to talk too much.
It may seem bizarre that a human being can be organised in this way. It's an alternative way of thinking and functioning, but it uses the same mental tools - the same brain - that we all have. If we all grew up under the same abusive circumstances as me, maybe we'd all operate in the way I did then.
Over the next few years, Dr Baer spent more time talking to my different personalities under hypnotherapy than he did talking to me. This gave me terrible headaches because the parts didn't always agree. Some of them started to keep a journal in which they could all write, but then one of the personalities burnt it.
My condition seemed to be getting worse rather than better.
Then, in the summer of 1996, Dr Baer received a memo from Holdon, the 34-year-old male in my group of alternate characters. As the protector of my "group", he had described a step-by-step procedure to help incorporate the other personalities into my own. Dr Baer and I were both utterly amazed.
That August, Dr Baer and I tried Holdon's integration process with Julie, my 13-year-old persona who was "born" at a time when my grandfather was molesting me. Julie was crippled and suffered breathing problems.
Under hypnosis, I "met" Julie in a place I visualised as secure, and Julie "stepped into" my body. With Dr Baer's help, I absorbed her thoughts, memories and character traits. The process seemed pretty easy - but the results were painful.
After Julie and I integrated, I immediately started feeling very sensitive to all sounds around me.
I was able to hear Dr Baer's breathing and the sound of his pen writing, the traffic below and the air conditioning. When he talked, it sounded as though he was screaming at me.
The "integration" felt like I'd gone through major surgery, and it left me with serious doubts about ever doing it again.
At home, my mind raced as if I were watching a movie in fast forward. As the memories of what had happened to me poured into me, I felt every pain associated with them - and even though each pain lasted only a few seconds, I just wanted these memories to stop.
During the next week, I worked through all the memories the Julie character had, and gradually I started functioning again.
I realised that having Julie had always been a form of protection from what had happened to me as a child - and now I was going to have to deal with the memories of the degradation myself.
We "integrated" Claire next - and the experience did not seem to take such a toll. Having Claire join my personality made me suddenly feel more feminine and more sensitive.
The process was long and hard, but it worked - and eventually we dealt with Holdon. After that, I could see changes in myself. It's hard to pinpoint, but I felt like more of a person. There was a new richness in everything about me - and in 2001 I divorced my husband after a troubled marriage.
It scared me to have to re-live and talk about what had happened, but the experience made me stronger.
Two years ago, I finally stopped having therapy, although I still see Dr Baer as a friend. Today, I don't lose hours of my life any more.
What I have come to understand is that when children are victimised, as I have been, they turn to the only safe place they know - within themselves.
I don't ever want to forget the different parts of me - they made me who I am - but I've missed so much of my life. Now I feel reborn.