For decades, researchers have focused on the psychological difficulties that present in dissociative identity disorder cases. But now they are realising there is another issue.

Typically, we associate dissociative identity disorder cases with multiple personalities or split personalities. So from the very start, we are exploring what’s happening with the identity or personality. As a result, previous studies have tended to look at the changing character traits of the person.

But things have changed. Now researchers know that people who suffer from this disorder can also undergo remarkable physical changes. And this is where it gets interesting. Because understanding how our minds can change our body could help in other medical areas.

Early Scientific Dissociative Identity Disorder Cases

Early scientific studies on dissociative identity disorder cases were pretty rudimentary. Dr. Morton Prince, a neurologist in the early 20th century, studied the galvanic skin’s response during multiple personality episodes. But later research showed that there were other, more advanced physical symptoms.

Patients reported a range of different symptoms, including:

  • headaches
  • heart palpitations
  • pain
  • gastrointestinal problems
  • changes in menstruation
  • sexual dysfunction
  • vision
  • handwriting

Researchers were able to record variations in brain wave activity, respiratory and cardiac activity, blood flow to the brain and more. It seemed incredible. In the past, the general consensus was that people with dissociative identity disorders were somehow malingering or fabricating their symptoms. Now there was real proof of a serious medical condition. So how is this even possible?

Dr. Frank Putnam is a psychiatrist and works at the Laboratory of Developmental Psychology at the National Institute of Health. He thinks it is easier to understand how the mind can influence the body if we look at ourselves in two parts. We have a ‘biological self’ and a ‘psychological self’. So when one switches, so does the other.

“We have a work self and a play self, for instance, but we are the same person. But each of those selves has its own repertoire of emotional states, memories and, to some extent, an underlying biological pattern. Those minor differences are seen in their extremes in the patients with multiple personalities.”

So when a person with dissociative identity disorder switches personality, they will also change biologically. Furthermore, these changes can be enormous.

“A given state of consciousness has its biological reality. Keeping these states separate and distinct, the patients create biologically separate selves.” Dr. Putnam

5 Examples of Dissociative Identity Disorder Cases


In one interesting case, a young man with dissociative identity disorder has no allergic symptoms drinking orange juice when he is his true self. But it appears that his other personalities are allergic. As such, when they take over, he experiences hives.

Stranger still is that if he drinks the juice as himself but a personality appears whilst it is being digested, the hives will still appear. Even more strange is that if he drinks the juice as another personality and has an allergic reaction, but then comes back as himself, the hives disappear.


One study examined a woman with an undiagnosed rash on her skin. This woman was admitted to hospital with an inexplicable rash on her left arm and was found to suffer from multiple personalities. Medical staff discovered that during the night, one of these personalities had been placing poison ivy on her left arm with her gloved right hand.  This caused the rash.

She had no knowledge of these nightly excursions. However, when access was restricted to the plant, lesions appeared on the left arm as usual. Dissociative identity disorder cases like these are helpful. This is because they diagnose patients with this disorder in the first instance when they might present with another condition.


This study examined the extraordinary ability of a blind woman who regained her sight. A 37-year-old blind German woman was able to see, but only when her personality switched to a teenage boy.

‘B.T’ suffered an accident at a young age which left her with damage to the visual processing area of the brain. This means her eyes function normally, but her brain cannot process the information it receives.

However, during a therapy session to help her cope with her dissociative identity disorder, BT suddenly regained her sight. As she switched between personalities, her vision also switched on and off like a light. BT managed to regain her sight in all of two of her personalities after months of therapy.

Eye Colour

A family had forced a woman to be present as they executed her boyfriend. As a result of this terrible trauma, she developed a dissociative identity disorder. The woman was dark-skinned with brown hair and brown eyes.

During a therapy session, she experienced a particularly disturbing flashback of the event. She questioned whether she could ever live a normal life again and turned to the therapist. Her eyes had changed from a deep brown to a bright blue. They remained that colour for about 10 seconds before changing back to brown.


Changes in handwriting are amongst one of the most common symptoms of physical changes in dissociative identity disorder cases. In fact, studies show that 37% of patients with the disorder report changes to their handwriting style.

Not only that, but when examined by forensic handwriting experts, analysis revealing striking differences between samples provided when switching between personalities. In fact, changes in handwriting are now such an indicator of dissociative identity disorder cases that experts are using it to diagnose patients.

This is because handwriting samples from the broader general public tend to convey a wider range of emotions and experiences. By contrast, samples from those with multiple personalities often reveal specific memories and emotions. And this can be helpful, not only in the diagnosis but in the treatment as well.

“They can teach us much about the mechanisms by which we shift from one state of consciousness to another,” Dr. Putnam said. ”Most of psychiatry deals with helping people shift from one unpleasant state to another, more pleasant one.”

What Research into Dissociative Identity Disorder Cases Can Show Us

These dissociative identity disorder cases show us the incredible power our minds have over our bodies. This demonstrates just how dramatic the changes can be if we can harness this extraordinary power in the right way.

Researchers believe that the key to better health is a move away from pharmaceuticals and using the power of our own bodies to heal. If we look at dissociative identity disorder cases, we can not only help those who suffer from multiple personalities but a wider population as well.

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