[The changes of PDD symptoms according to their mental growth].

We proposed and compared 3 cases with PDD whose clinical problems are varied according to their mental growth. Although common clinical symptoms were not found, when deciding their behavior, all of the cases have different priorities to people withoue PDD, and their relationship with social interaction was confused. Our understanding is that concept of "developmental disorder" may be helpful to comprehend young adults' behavioral problems, though it may have some risk for over-diagnosing.