what is DID/OSDD? : what is DID / OSDD? Dissociative identity disorder, formerly known as Multiple personality disorder is a traumatic / dissociative disorder that occurs from childhood trauma around the ages of 5 to 9 years old
the body's mind after said trauma will basically "split" into altered states of consciousness also known as alters, these alters are created as a base of helping the body heal from said trauma / avoid it in the future

as the body grows older, the more the system will become more noticeable
most systems to be diagnosed are usually in their late teens - early adulthood and is rare for someone under 16 to be professionally diagnosed (does not mean someone under 16 doesnt have did; a person's did forms during childhood after traumatic events)
diagnosis of did is difficult as not many specialists are knowledgeable on dissociative disorders
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despite the myth that did is rare; the stats only count those who are professionally diagnosed & doesnt consist of systems who havent gotten a professional diagnosis