High Quality Content by WIKIPEDIA articles! Acceptance and commitment therapy or ACT (typically pronounced as a word, not as separate initials) is a cognitive–behavioral model of psychotherapy. It is an empirically-based psychological intervention that uses acceptance and mindfulness strategies mixed in different ways with commitment and behavior-change strategies, to increase psychological flexibility. The approach was originally called comprehensive distancing. It was developed by Steven C. Hayes, Kelly Wilson, and Kirk Strosahl.