Dissociative Identity Disorder, formerly known as Multiple Personality Disorder or Split Personality Disorder, is a disorder in which a person has multiple alters, or headmates, who can take control of the body, not always willingly.

There are many disorders that all fall under the category of dissociation, but DID is the most rare and most severe disorder. The most believed cause of said disorder is severe repeated trauma, most often in childhood. DID can take form at any age. It is believed that only about 1.5% of the global population has it without either gender having a distinct difference, however with how difficult it may be to diagnose, there may be a much higher percentage. 

Due to trauma, it may cause fragmented amnesia, meaning that one alter may have the memories from an event while another may not have any recollection of the event. This is most common during a “possession”, where an alter takes over entirely versus a “non possession” where you are just viewing from the outside. 

Impairment due to Dissociative Identity Disorder can be extremely widespread, where one person diagnosed with it cannot handle the outside world, and another person can live a much more chaotic life with kids and a partner. As many people who have DID have other mental illnesses, most commonly schizophrenia, depression, anxiety and (C-)PTSD. 

Unfortunately, there are many movies and shows that portray those with DID as some horrible villain, being the “good guy” one moment and then the next a “bad guy” when that is hardly the reality. In many systems, what some people with DID have decided to call their group of alters, switching quickly between alters and who is out is very difficult and can be extremely tiring. 

Another issue with the assumption of an evil alter and a good, there are different tasks that many alters carry out. Some different jobs that may be taking place are things like, “protector”, “trauma holder”, “gatekeeper” and more. The main job of alters is almost always to protect the “host”, the original person. Although the host is not always the original person, the host may be the person who is out most.

Alters are primarily formed during high moments of stress or traumatic events and their job may be directly related to that. For example, if it was an extremely stressful event that caused the fracture that brought them into existence, their job in the system might be to be the “chill pill”. Of course, this isn’t the same for every person who has DID, many people who have this disorder are left feeling out how it works by themselves with little guidance. There is no limit in the amount of alters one may have, as after the alter is no longer needed for their task, they may go dormant (or go to sleep). Alters cannot die, so they may go dormant for years before appearing again, or may not front again, but they are always somewhere in the headspace. 

It is possible to integrate all the alters and the host back into one person, as if “repairing” the “fractures” that took place through intense therapy. If this is not desired, one may take medications to help with the other mental illnesses that often occur with Dissociative Identity Disorder, but so far there is no known medication to cure or lessen the disorder alone. 

Hopefully in the future there will be more research available for Dissociative Identity Disorder, but as of now if you wish to learn more there are resources online, especially YouTubers who document their own experiences.