Son, 7, with asperger syndrome hold urine for extended periods of time (14-16+ hrs) regularly, sometimes to the point of pain. what can we do?

Aspergers: I'm actually working with a client struggling with this same issue. For him, it was about control and fear of change. He did not want to move classrooms. The teachers told him that until he used restroom at school he could not change and...No urination. I often see this as sensory, environmental, and control. A good licensed child psychologist familiar with aspergers and anxiety will help!