ACT is a type of psychological intervention that focuses on the development of psychological flexibility, or the ability to contact the present moment and accept negative thoughts without judgment. Created by Steven C. Hayes, Kirk D. Strosahl, and Kelly G. Wilson, ACT focuses on directing behavior in ways that match clients’ core values. Unlike cognitive behavioral therapy, ACT does not stress the importance of controlling thoughts, feelings, or mental health disorder symptoms; instead, ACT therapists encourage their clients to accept their feelings unconditionally, even when those feelings are initially very painful. Therapists using ACT help their clients define a set of core values—goals or states of mind that are important to the client. With these core values in mind, the client commits to acting in ways that reinforce and further these values regardless of the limits and restrictions imposed on them by their condition. The six core principles of ACT are cognitive defusion, acceptance, contact with the present moment, observing the self, values, and committed action. ACT has been proven effective for the treatment of depression, anxiety, stress, addictions, eating disorders, schizophrenia, borderline personality disorder, and myriad other mental health issues.