Where do you have this from?
There are contradictory results. While some samples found a mean age of onset around the age 16, other studies found a mean age of onset of around 22 years.Bro this study was made in the 80s at that time the amount of data available about dpdr was almost none. The psychiatrist community definitely change their view about the onset age about dpdr. Actually if you see the new studies they will show that dpdr is more common to start in teenages than adults.