The estimates for the number of people with DID(MPD) varies widely. But one group of researchers say that one per cent of the general population and as many as five to twenty per cent of people in psychiatric hospitals may have DID(MPD), and ninety-eight to ninety-nine per cent of them have histories of trauma that was repetitive, overwhelming, and/or life threatening. Also, this trauma generally happened at a sensitive age which is normally before age nine.
DID(MPD) is often misdiagnosed because the symptoms are similar to those of psychiatric disorders. People with DID(MPD) go through periods where they do not associate and the disorder may be missed in a clinical examination. On average, people with DID(MPD) spend seven years in treatment before an accurate diagnosis is made (Multiple Personality, internet). They go from one therapist to another, medication to medication with treatment only for symptoms but no progress is made toward curing the disorder. Many people with DID(MPD) do not know they have alters and because it has occurred for so long, they think that time loss is normal.
The symptoms for childhood DID(MPD) are similar to those that adults have. Some are subtle, alternating personality changes like a shy child having depresses, angry seductive, and /or regressive episodes. These children have a history of abuse, and they develop amnesia that makes them forget abuse and/or other recent events such as their schoolwork, angry outbursts, and regressive behavior. They also experience differences in their ability to do things like school work, play games and listen to music. They may go into trance-like states, hear hallucinating voices, experience intermittent depression, or have denied behaviors, causing them to be called liars.
In childhood DID(MPD) the number of personalities are fewer. The average age for adults with DID(MPD) is thirteen, but for children the average age is four (Coons, internet).