Abused toy.....

short answer is that every location has their own standards of what is what with mental disorders.

here in the USA treatment providers have to fill out forms and send them to places that gather their answers with other treatment providers and put together this makes a census, demographics and statistics.

here in america everyone has to fill out a census form. this census taking for the whole country for every person in the country tells the government things like population, which areas of the country has more people, what mental disorders and physical challenges americans have, what kinds of services americans need and much more.

america also has an agency called the american psychiatric association. this agency is responsible for putting together things lik what each mental disorder in america is, what things americans must meet in order to be diagnosed that mental disorder.... a whole bunch of stuff.

my point all these documentations add up so that places like mental health agencies, doctors, the center for disease control and so on can form a picture of things like what causes this to happen, age of onset of that mental disorder, how to diagnose a mental disorder and how to treat it....

some of this happens at the country level, some at the state level and some at the federal level...

my county and state mental health demographics/ statistics state all those reported on the census's and other reports that treatment providers in my county and state have reported say DID...........begins........ in very early childhood due to extreme trauma, even if a person doesnt actually get their ...........diagnosis.......... of DID until after they are a teen ager or adult, the reported cases have shown that their DID ..........began....... before the age of 5.

you can find out what your locations demographics/ statistics/ reported cases for your location are by contacting your center for disease control, mental health agencies or by going to your local library and telling the person at the customer service desk you would like information on the annual census reports, mental health demographics and statistics for your county and state. these documents are kept in books in the reference department of libraries.

As for the 17 yr old in your post, only they can explain the hows and whys they are DID and when....maybe you can ask them if they meant a doctor .......diagnosed........them as being DID at 17.