Acceptance and Commitment Therapy

Acceptance and Commitment Therapy (ACT) is a form of cognitive-behavioral therapy (CBT) that aims to increase psychological flexibility: the ability to stay in contact with the present moment and choose behaviors in line with one’s values, even in the face of difficult thoughts and feelings.

ACT does not try to remove unwanted thoughts and feelings. It teaches skills that lessen their impact and importance instead. People can then pursue valued life directions even when unpleasant experiences persist.

ACT’s overarching goal is not symptom reduction per se. It is a more vital life guided by values, the qualities of action a person chooses to live by. ACT pursues this through acceptance, mindfulness, and behavior change.

This article is for informational and educational purposes only and is not intended to be a substitute for professional medical advice, diagnosis, or treatment.

Always seek the advice of your physician, therapist, or other qualified health provider with any questions you may have regarding a medical or mental health condition.

Never disregard professional advice or delay in seeking it because of something you have read on this site.

When is ACT used?

ACT is a transdiagnostic approach, meaning it can be applied to a wide range of psychological problems rather than a single disorder.

Randomized controlled trials support the efficacy of ACT for a variety of conditions, including:

• Anxiety disorders
• Depression
• Substance use
• Chronic pain
• Psychosis
• Obsessive-compulsive disorder
• Eating disorders
• Behavioral health concerns like smoking, diabetes management, and weight control

Research has since extended ACT beyond its original remit. That includes presentations once thought too severe for an acceptance-based approach.

Morris et al. (2024) reviewed two decades of work on ACT for psychosis. It showed meaningful effects in individual and group formats. Outcomes included rehospitalization, depression, and distress from psychotic symptoms.

Open questions remain. These include how ACT differs from similar approaches and how support staff should be trained.

Reyes-Ortega et al. (2020) studied 65 people at a borderline personality disorder clinic in Mexico City. They received brief ACT, brief dialectical behavior therapy, or a combined package that added functional analytic psychotherapy.

All three groups improved, with no differences between them. Gains were related to reduced experiential avoidance and better mindfulness skills.

For chronic pain, McCracken and Vowles (2014) reviewed cognitive-behavioral treatment and identified ACT and mindfulness-based approaches as areas with potential for future progress.

ACT has also been tested in physical health settings. A randomized trial of 39 bariatric surgery patients compared it with usual follow-up.

ACT improved eating-disordered behaviors, body dissatisfaction, and quality of life (Weineland et al., 2012).

Among 78 people with visible burn injuries, appearance anxiety was linked to lower acceptance and defusion (Shepherd et al., 2019). That study was cross-sectional. It shows an association, not a treatment effect.

ACT may be especially well-suited to chronic conditions involving experiential avoidance: persistent attempts to escape unwanted thoughts and feelings. Paradoxically, these attempts increase the frequency and impact of what is avoided.

Origins and Theory of ACT

ACT grew out of laboratory research on human language rather than clinical case studies. Steven C. Hayes and colleagues built it on a behavior-analytic account of how language shapes thought (Hayes, 2004).

Relational Frame Theory and the Third Wave

Relational frame theory (RFT) explains how humans learn to relate things to one another arbitrarily. A printed word, a spoken sound, and a physical object can all come to mean the same thing.

Hayes argues that this ability underlies human language and higher thinking. It also carries a clinical cost (Hayes, 2004).

Once a thought can be linked to almost anything, verbal rules can start to dominate behavior. A rule such as “I must never feel anxious in public” is harmless in itself. Obeying it rigidly is not. Imagine rearranging your whole life to avoid public anxiety.

Trying to push such thoughts away also tends to backfire, as ironic process theory shows.

Hayes places ACT in a “third wave” of behavioral and cognitive therapies (Hayes, 2004). Each wave changed the clinical target.

• First wave: Classical behavior therapy used conditioning-based methods, such as systematic desensitization, with no reference to cognition.
• Second wave: Beck’s and Ellis’s cognitive therapies added a focus on the content and correction of thoughts.
• Third wave: ACT shifts the target to a person’s open, values-guided relationship with their own thoughts.

Dialectical behavior therapy and mindfulness-based cognitive therapy belong to the same wave. All three keep earlier techniques but add acceptance, mindfulness, and values.

Psychological Flexibility and Workability

Where Beck’s cognitive therapy centers on correcting distorted thinking, ACT centers on psychological flexibility. This is the ability to contact the present moment. As the situation allows, it means persisting with or changing behavior in service of chosen values (Hayes et al., 2006).

Kashdan and Rottenberg (2010) reviewed evidence that psychological flexibility is a fundamental aspect of health.

They noted that these flexibility processes are absent in many forms of psychopathology. That helps explain why ACT works across diagnoses.

ACT judges a thought by its workability, not its truth. The question is not “Is this thought true?” but “If I act as though it is true, does that move me toward the life I want?”

The opposite of flexibility is experiential avoidance. Examples include skipping a job interview to avoid anxiety, or drinking to numb grief.

Therapy often opens with creative hopelessness, a non-judgmental review of how well past attempts at control have worked. The aim is not despair. It is to loosen the grip of the control agenda and make room for acceptance.

How ACT works

ACT relies on six core processes to build psychological flexibility:

Psychologists often draw these processes as a hexagon, the hexaflex (Hayes et al., 2006). They fall into two overlapping sides. The mindfulness and acceptance side covers acceptance, defusion, present-moment contact, and self as context. The commitment and behavior-change side covers values, committed action, present-moment contact, and self as context.

Acceptance

Rather than fighting unwanted feelings, acceptance involves making space for them, allowing them to come and go without struggle.

Acceptance is not passive resignation, liking the discomfort, or giving up on change. It means dropping an unworkable struggle with inner experience. The energy once spent fighting it becomes available for valued action.

Therapists help clients practice acceptance through exposure exercises and metaphors that encourage adopting an open, receptive stance toward internal experiences, even if they are unpleasant.

The goal is to contain difficult feelings lightly, like holding a delicate flower, rather than crushing them with avoidance attempts.

For example: A client with panic disorder may practice acceptance by intentionally bringing on mild sensations of dizziness or breathlessness, observing them with curiosity rather than trying to control or eliminate them.

Cognitive Defusion

Cognitive defusion techniques aim to reduce the impact of unhelpful thoughts by changing one’s relationship to the thought rather than the thought itself.

The state defusion loosens is called fusion. In fusion, a thought feels like reality. “I’m going to fail” feels like an accurate prediction rather than one passing mental event among many.

Through defusion, clients learn to view thoughts as transient mental events rather than literal truths that dictate behavior.

Defusion exercises include labeling thoughts as thoughts (e.g., “I’m having the thought that I’m unlovable”), speaking thoughts in silly voices, or rapidly repeating a word until it loses meaning.

For example: A client struggling with self-critical thoughts may practice defusion by singing their thoughts to the tune of “Happy Birthday,” creating distance from their literal meaning.

Being Present

ACT teaches mindfulness skills to help clients contact the present moment rather than dwelling on the past or worrying about the future.

Exercises such as noticing the breath, observing sounds, or scanning the body cultivate flexible attention to current experience.

This is a trainable skill. It teaches people to notice fusion or avoidance as it starts. That makes present-moment contact a precondition for using the other processes when they are needed.

Therapists also help clients attend to the present during sessions, tracking subtle emotional and behavioral responses as they occur.

For example: During a session, the therapist may invite the client to pause and notice five things they can see, four things they can touch, three things they can hear, two things they can smell, and one thing they can taste, grounding them in the present moment.

Self as Context

Self as context refers to contacting a transcendent sense of self that is distinct from one’s passing thoughts, feelings, and experiences.

Through metaphors and perspective-taking exercises, clients access a continuity of consciousness that has been present throughout their lives, like a boundless sky holding various weather patterns.

This flexible sense of self provides a vantage point from which to notice internal experiences with greater equanimity and choice.

ACT contrasts this observing self with the conceptualized self. That is the running self-story built from labels, roles, and judgments, such as “I am a failure.” People can fuse with it and defend it as fixed fact.

Another metaphor pictures the self as a chessboard. Thoughts and feelings are pieces locked in conflict. The person is the stable board that holds the whole game.

For example: The therapist may guide the client through the “Observer Exercise,” inviting them to recall a difficult childhood memory, then step back and notice that the “you” observing the memory is the same “you” that is present now, untouched by the painful experience.

Values

Values work involves identifying chosen life directions: deeply meaningful qualities of action that can guide behavior.

A value is different from a goal. Goals are specific endpoints you can complete, such as finishing a report. Values, such as being a patient parent, are lived out moment by moment. They are never finished.

Therapists help clients clarify values through reflection, assessment, and experiential exercises, while undermining rigid rules that restrict vitality.

Meaningful moments invariably reflect valued actions, while painful experiences contain opportunities to recommit to values like love and growth. Values are held lightly yet earnestly, as welcome companions on the ongoing journey of life.

For example: The therapist may invite the client to write a eulogy for their 80th birthday, reflecting on what they would want their loved ones to say about the qualities they embodied and the impact they had on others’ lives.

Committed Action

Committed action entails setting goals guided by one’s values and taking concrete steps to achieve them.

Behavior change strategies from across therapies can be applied, such as exposure, skill acquisition, or habit reversal.

The key is that change efforts are linked to chosen values and grounded in acceptance and defusion. Barriers invariably arise. But psychological flexibility allows recommitting to valued action again and again.

For example: A client who values environmental stewardship may commit to specific actions like biking to work, volunteering for beach cleanups, and reducing their plastic consumption, even when inconvenient or uncomfortable.

How effective is ACT?

Numerous studies have investigated the effectiveness of Acceptance and Commitment Therapy (ACT) for a wide range of mental health conditions.

Large Meta-Analyses of ACT

A-Tjak et al. (2015) pooled 39 randomized controlled trials to test how well ACT works for mental and physical health problems.

This is strong evidence against no treatment and weak controls. “No difference from CBT” is a smaller claim. It also fits the possibility that ACT and CBT share ingredients such as the therapeutic relationship.

A more recent meta-analysis focused on depression. Bai et al. (2020) pooled 18 studies with 1,088 participants.

ACT significantly reduced depressive symptoms compared with control groups (SMD = 0.59). The benefit was significant after treatment (SMD = 0.62). It held at three-month follow-up (SMD = 0.55).

Gloster et al. (2020) took a wider view. They reviewed 20 meta-analyses reporting 100 controlled effect sizes across 12,477 participants.

ACT was efficacious for anxiety, depression, substance use, pain, and transdiagnostic groups. It generally beat inactive controls and treatment as usual. It also beat most active treatments, though not CBT.

Importantly, these meta-analyses also found that the effectiveness of ACT was maintained over time, with benefits often persisting at follow-up assessments several months after treatment. This suggests that ACT may lead to lasting improvements in mental health.

Contemporary Research

The newest evidence tests ACT against the toughest comparison: other genuinely active therapies.

An earlier review by Öst (2014) pooled 60 trials with 4,234 participants. The mean effect was small (g = 0.42). Against other cognitive or behavioral treatments it was small and not significant (g = 0.16).

Gower et al. (2026) then set ACT its fairest test, summarized below.

The authors also found common weaknesses in the ACT trial literature. These include no preregistration of primary outcomes, too little power to detect differences between treatments, and limited intent-to-treat analyses.

Progress will need more rigorous comparative trials. It will also need idiographic designs, which study how treatment works for the individual case. Those suit ACT’s flexible, case-by-case approach better than standardized trials.

ACT clearly beats no treatment and often keeps its benefits at follow-up. Whether it beats other established therapies is a different question. So far, trials show no clear advantage.

Possible limitations

While ACT has demonstrated efficacy for a range of concerns, it may not be the optimal fit for every individual or situation.

The open, experiential nature of ACT can initially feel challenging for clients accustomed to more structured, didactic therapies (Hayes et al., 2011).

ACT asks clients to accept discomfort and pursue valued actions despite unpleasant internal experiences. That is a hard sell for some clients.

It may not resonate with clients seeking quick symptom relief (Lee et al., 2021). Nor may it suit those who believe happiness depends on eliminating suffering.

Culture matters too. ACT’s focus on personal values and individual choice may need adapting. Some cultures prioritize social harmony or interdependence over autonomy (Hayes & Lillis, 2012).

Most trial research draws heavily on Western samples. Cross-cultural replication is still needed.

ACT is transdiagnostic, but some clients need a slower, more concrete approach. These include people with active psychosis, severe depression, or cognitively demanding conditions.

They may also need close coordination with their medical providers to ensure safety and engagement (Hayes et al., 2011). Training is another open question. Morris et al. (2024) note it is still unclear how support staff should be trained to deliver ACT for psychosis.

Evidence for ACT’s six-process model is encouraging but incomplete. Hayes et al. (2006) called it broadly supportive but immature.

A later meta-analysis of 66 laboratory studies found significant effects for acceptance, defusion, present-moment, and values components (Levin et al., 2012). Experiential methods such as metaphors and exercises outperformed a rationale alone.

The six processes also overlap. That makes them hard to separate experimentally. It can also make training clinicians to a high standard more demanding.

What to Expect in ACT

Below are things to expect if considering ACT:

• Session Format: Sessions often use mindfulness practices, experiential exercises, metaphors, and role-plays to build present-moment awareness and illustrate ACT processes.
• Therapist Stance: Therapists take a non-judgmental, compassionate stance while encouraging clients to practice new ways of relating to internal experiences in service of their values.
• Home Practice: Between-session practice is critical for applying acceptance, defusion, and values-based action skills to real-world challenges.
• Temporary Distress: Clients may temporarily experience increased distress as they confront previously avoided thoughts, feelings, and situations.
• Over Time: Clients often report increased vitality, self-compassion, and ability to handle life’s difficulties.
• Overall Aim: ACT aims to help clients build meaningful lives by embracing both the joys and sorrows of the human experience.

As Russ Harris, a physician and well-known ACT trainer, explains in The Happiness Trap (2007), ACT’s practical core is three linked moves. Open up to difficult thoughts and feelings. Connect with what matters. Then take action guided by it.

Harris also argues that the everyday pursuit of constant positive feeling is itself a driver of suffering. That is one practitioner’s view, not a settled finding.

Patients’ own accounts add texture. Bendelin et al. (2020) interviewed 11 people after internet-delivered ACT for chronic pain. Participants described changes in their attitude to pain and in “acting with pain.” The authors noted that therapist guidance and homework deadlines played complex roles in autonomy and change.

ACT vs CBT

While ACT and traditional CBT share behavioral roots, they differ in important ways. Both approaches target cognition. CBT seeks to modify irrational thought content. ACT aims to alter the context and function of cognition, meaning whether thoughts are believed and acted upon.

ACT assumes painful thoughts are a normal product of human language, not necessarily a distortion. Arguing with your own mind is often a losing battle. So ACT asks how much power a thought has over behavior. Workability, not truth, is the test.

Additionally, CBT focuses more on symptom reduction, while ACT emphasizes pursuing a meaningful life in the face of symptoms.

Feature	CBT	ACT
Main target	The content of distorted thoughts	A person’s relationship to their thoughts
View of thoughts	Tested against evidence and replaced with balanced alternatives	Observed as passing mental events; truth is secondary
Key question	Is this thought accurate?	Does acting on it move me toward the life I want?
Treatment goal	Symptom reduction	A meaningful, values-guided life alongside symptoms
Typical methods	Thought records and behavioral experiments	Defusion, acceptance, and values clarification

For example: Faced with the thought “I’m going to fail this presentation,” a CBT therapist may ask the client to weigh the evidence for and against it. An ACT therapist is more likely to help the client notice it as a thought, make room for the anxiety, and then give the presentation anyway.

Still, both therapies recognize the importance of the therapeutic relationship, behavioral rehearsal, and aligning treatment with the client’s goals.

Direct comparisons with CBT show no clear winner. A-Tjak et al. (2015) found no significant difference between ACT and established treatments such as CBT.

Gloster et al. (2020) found ACT generally superior to most active treatments. CBT was the exception. The strictest test, by Gower et al. (2026), found no difference from other bona fide therapies.

However, more research directly comparing ACT and CBT is needed to clarify their relative efficacy.

Many contemporary CBT approaches now borrow from ACT. They incorporate elements of acceptance and mindfulness from contextual approaches. ACT protocols for specific disorders, in turn, often include traditional behavioral components.

Rational emotive behavior therapy sits furthest from ACT. It disputes absolutist “musts” and “shoulds” directly, while ACT changes the relationship to them.

Ultimately, the approaches can be seen as complementary, with different means to the shared end of reducing suffering and improving clients’ lives.

References

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