Decoding consciousness

Studying DID could give us an insight into the nature of consciousness

One of the odder mental disorders is dissociative identity disorder (DID), which is often referred to as multiple personality disorder. It occurs when the same individual displays two or more different personalities (sometimes many more), which are alternately in control.
 
It can vary from the mild to the severe. The personalities are often very different. Usually one personality is dominant and in charge most of the time, with alternates taking charge occasionally. There are indications that in some case (s), two different personalities may be in charge at the same time, or changeover might happen in seconds. One personality may not have any memory of the others, or of actions committed by the others, and there could be marked changes in opinions, tastes in food, clothing, sexual orientation etc.

 
DID is believed to occur when individuals have been highly traumatised by some event, or abuse. The diagnosis depends on observed changes in behaviour, consciousness, memory, perception, cognition etc. Patients have big gaps in memories, with spotty recollections of people, places, and events, that cannot be normally explained. Their abilities and skill sets may be very different too.
 

The first well-documented case was studied in 1791. A 20-year-old woman living in Stuttgart, Germany was alternately the "French woman" and the "German woman." The French woman spoke perfect French, behaved like an aristocrat, and knew about the German woman. The German woman had no idea of the French woman's existence, and spoke German.

 
In 1979, Juanita Maxwell beat Inez Kelly to death with a reading lamp after an argument in a hotel in fort Myers, Florida. Or rather, "Wanda Weston" did. The 25-year-old Maxwell had no memory of the dispute that led to the assault. Her alternate personality, Wanda (who claimed to a be a childhood friend of Maxwell) confessed to the deed.
 
Recently, it was shown that DID can be diagnosed by MRIs and EEGs. In 2015, a case was reported in Germany where a patient with several personalities claimed to be blind, although she had perfectly functional eyesight in physical terms. (https://onlinelibrary.wiley.com/doi/pdf/10.1002/pchj.109).

 
Some of the alternate personalities responded to psychiatric therapy to the point where those personalities regained eyesight, whereas others remained blind. EEGs showed that, while a "blind personality" was in control, the parts of the brain where visuals are processed remained inactive, even though the eyes were open and focused. However, when a "sighted personality" was in control, her brain’s vision processing activity was normal.
 
This evidence gelled with an earlier study where researchers studied people suffering from DID, and compared their brain scans to actors, who had been asked to pretend to be DID sufferers. The actual patients had identifiable differences, which means that somebody shamming DID could be caught by EEGs and MRI scans.

 
This disorder has been reported in medical literature many times, with many different cases reported in the last 200 years from different places and cultures. Anecdotal evidence suggests that many famous cases of people suffering "possession", being overtaken by "spiritual ecstasy", or just behaving strangely and forgetting their actions, could actually be cases of DID.
 
There was a very well-known American footballer, Herschel Walker, who referred internally to his athletic personality as "the warrior", and his off-the-field persona as "the hero". When he accepted awards as the "hero", he couldn't remember his achievements as the "warrior". He was diagnosed and received treatment only after he retired.

 
Consciousness is also associated with personal experience. Each of us experiences the world, the food we eat, the journeys we take, the hobbies we enjoy, in different ways. This is actually true even when two people eat the same food, or travel on the same train. Suppose, for example, that one person loves coriander while another hates it. Different parts of their brains show activity when they eat coriander.
 
DID leads to the same person experiencing the same things in different ways, depending on which alternate personality is in charge. Blindness is an extreme form, but tastes in music or food, may differ as sharply for alternate DID personalities, as for different people.

 
Apart from the possible ways in neuro-imaging advances could lead to improved diagnosis, and treatment for DID sufferers, this discovery has interesting implications for the broader understanding of consciousness. Each individual’s internal processing of the world is unique.
 
One of the toughest problems in medicine (and philosophy) is consciousness. Why is something or somebody conscious, or unconscious? We can define the structural or physical signals associated with consciousness (such as brain activity, movement, speech). But we still don’t know why. Maybe a study of DID using modern medical technologies will give us an insight into the nature of consciousness itself.