What is Acceptance And Commitment Therapy?
Acceptance and Commitment Therapy (ACT, pronounced as the word “act”) is a form of cognitive-behavioral psychotherapy that aims to increase psychological flexibility—the ability to remain present with difficult thoughts and emotions while taking action aligned with personal values. Unlike traditional cognitive-behavioral approaches that focus on changing or eliminating distressing thoughts, ACT teaches clients to accept internal experiences without struggle and commit to behavior changes that serve what matters most to them. The therapy emerged from behavioral science and is grounded in Relational Frame Theory, a psychological account of how human language and cognition contribute to psychological suffering.
Origins & Lineage
ACT was developed beginning in the late 1970s and through the 1980s by clinical psychologist Steven C. Hayes at the University of North Carolina at Greensboro, later continuing his work at the University of Nevada. Hayes’s personal experience with disabling panic attacks—which conventional therapies failed to address—became a catalyst for the development of ACT’s core philosophy: that struggling against one’s own thoughts and emotions often intensifies suffering rather than relieving it.
The foundational concepts were formally introduced in Hayes’s 1987 article in Behavior Therapy, though the term “Acceptance and Commitment Therapy” did not appear until the early 1990s. The approach was fully articulated in the 1999 book Acceptance and Commitment Therapy: An Experiential Approach to Behavior Change, co-authored by Hayes with Kirk Strosahl and Kelly G. Wilson. This text established ACT as a “third wave” cognitive-behavioral therapy, distinguishing it from earlier behavior therapy (first wave) and cognitive therapy focused on thought restructuring (second wave).
ACT is rooted in B.F. Skinner’s radical behaviorism and functional contextualism, but also draws from Zen Buddhism and mindfulness traditions, existential and humanistic psychology, and operant conditioning principles. Its theoretical foundation rests on Relational Frame Theory (RFT), developed by Hayes and colleagues in the 1990s, which explains how human language creates both the capacity for complex thought and the conditions for psychological inflexibility.
How It’s Practiced
ACT operates through six core processes, often visualized as the “Hexaflex” model: acceptance, cognitive defusion, contact with the present moment, self-as-context, values clarification, and committed action. In practice, a therapist works with clients to identify areas of psychological inflexibility—where avoidance of uncomfortable internal experiences limits valued living—and applies specific interventions targeting these six processes.
Cognitive defusion techniques help clients observe thoughts as mental events rather than literal truths. Common exercises include repeating a distressing word until it loses emotional charge, visualizing thoughts as leaves floating down a stream, or saying difficult thoughts in silly voices. Acceptance practices teach clients to make room for uncomfortable emotions rather than suppressing them. Values work involves clarifying what truly matters across life domains (relationships, work, health) and distinguishing values from goals. Committed action translates values into concrete behavioral steps, even when discomfort is present.
Sessions typically blend experiential exercises, metaphors, mindfulness practices, and behavioral homework. An ACT therapist might use the “Passengers on the Bus” metaphor to illustrate how thoughts and feelings can be present without controlling behavior, or guide a “values clarification” exercise where clients imagine their own funeral to identify what they want their life to stand for.
Acceptance And Commitment Therapy Today
ACT has expanded significantly since 1999, with over 1,000 randomized controlled trials demonstrating effectiveness for anxiety, depression, chronic pain, PTSD, substance use disorders, eating disorders, psychosis, and work-related stress. It is practiced in dozens of countries and has been adapted for brief interventions, group therapy, workplace settings, and specialized populations including adolescents and trauma survivors.
Seekers encounter ACT through individual therapy with trained clinicians, self-help books (such as The Happiness Trap by Russ Harris and Get Out of Your Mind and Into Your Life by Steven Hayes), online courses, workshops, and group programs. Training opportunities range from multi-day immersion workshops to certification programs offered by organizations including PESI, Praxis Continuing Education, the Association for Contextual Behavioral Science (ACBS), and programs taught by Hayes, Harris, and other ACT trainers. There is no single official certification body, though various organizations offer tiered training and registration systems.
Common Misconceptions
ACT is not about achieving a state of constant calm or eliminating negative thoughts and feelings. The goal is not symptom reduction per se, but increased ability to live according to values regardless of internal states. Acceptance does not mean resignation or passivity; it means ceasing ineffective struggle with internal experiences in order to engage more fully with life.
ACT is also not simply mindfulness meditation repackaged as therapy. While it incorporates mindfulness as one component, it is grounded in a specific behavioral theory (RFT) and includes action-oriented change processes alongside acceptance-based ones. It does not pathologize difficult emotions or frame them as problems to be solved, but rather as natural parts of human experience that need not dictate behavior. Finally, ACT is not opposed to other therapeutic approaches; many practitioners integrate ACT with CBT, DBT, trauma-focused therapies, and other modalities.
How to Begin
For those new to ACT, Russ Harris’s The Happiness Trap (2008) offers an accessible introduction to the model with practical exercises. Steven Hayes’s Get Out of Your Mind and Into Your Life (2005) provides a more experiential workbook approach. The 1999 Hayes, Strosahl, and Wilson text remains the definitive clinical manual for professionals.
To experience ACT in practice, seek a therapist trained in the approach through the Association for Contextual Behavioral Science directory (contextualscience.org) or through directories of licensed therapists with ACT specialization. Many practitioners offer ACT-informed therapy even without formal ACT-specific certification. Online training courses from Russ Harris (Psychwire) and Steven Hayes (act.courses) provide structured learning for both clinicians and interested individuals. Local workshops, peer consultation groups, and the annual ACBS conference offer community and deeper training for those wishing to integrate ACT professionally.