Trevor played on his own, but simply did not play with other kids. After several hyperbaric oxygen therapy sessions for his autism, he picked up a ball, walked it back to his brother, and handed it to him. This was the first interactive play he had exhibited. Previously, Trevor might chase the ball, and he might pick it up. He would however never interact with a person. This behavior increased, and after additional hyperbaric oxygen treatments, Trevor continued interacting more often and at a greater level of depth with family, and eventually other people.