Corbett was the Founder of Dual Diagnosis Anonymous and used his personal recovery experience returning from Vietnam with his own dual disorders of heroin addiction and obsessive-compulsive disorder to create this highly successful peer support movement. He established DDA meetings in virtually every county in Oregon plus groups in many other states and even in other countries. He also innovated the creation of DDA groups and discussions within Oregon state hospital for patients, staff and members of the community. His legacy lives on in these self-help settings as well as the powerful personal influence he had on all those who met him. No one ever forgot him after meeting him.