ACT is Acceptance and Commitment Therapy.
Instead of changing your emotions or feelings, ACT focuses on changing your behavior. A central tenet of ACT is that mental health disorders are caused by reactions to unpleasant emotions such as anxiety and discomfort.
The ACT requires its participants to investigate their own fundamental values. Then, they are asked to devise objectives that will assist them in better embodying these values.
The objective is to accept all emotions, even the negative ones, and to modify your behavior so that it better reflects your fundamental values. On this basis, it is believed that one can begin to live a better existence and feel better. The efficacy of ACT as a standalone therapy requires further investigation.