ACT: Acceptance and Commitment Therapy

Acceptance and Commitment Therapy (ACT) is a third-wave cognitive-behavioural therapy developed by Steven C. Hayes and colleagues. Rather than targeting the content of unhelpful thoughts — as traditional CBT does — ACT aims to change the person's relationship with their inner experiences. The goal is psychological flexibility: the ability to act in accordance with chosen values even when difficult thoughts and feelings are present. ACT uses six core processes organised in the hexaflex: acceptance, cognitive defusion, present-moment contact, self-as-context, values, and committed action.

The key difference is the treatment target. Traditional CBT identifies unhelpful thought patterns, evaluates their accuracy, and replaces them with more balanced alternatives. ACT does not challenge the content of thoughts: instead, it uses cognitive defusion techniques to reduce their impact without changing what they say. ACT also differs in its explicit focus on values: rather than symptom reduction as the primary goal, ACT orients clients toward living a valued life even in the presence of psychological distress. Finally, ACT has a distinct theoretical basis — Relational Frame Theory — rather than Beck's cognitive model.

Psychological flexibility is ACT's central therapeutic target — the ability to contact the present moment fully, and to persist in or change behaviour in service of chosen values, even when difficult thoughts and feelings arise. Psychological inflexibility is the opposite: behaviour dominated by experiential avoidance (escaping unwanted inner experiences) and cognitive fusion (treating thoughts as literal truths). The six processes of ACT — acceptance, defusion, present-moment contact, self-as-context, values, committed action — each directly target a dimension of psychological inflexibility.

The six core processes of ACT, organised in the hexaflex model, are: (1) Acceptance — opening to experience without unnecessary struggle; (2) Cognitive defusion — creating distance from thoughts so they are seen as mental events rather than facts; (3) Present-moment contact — mindful engagement with what is happening now; (4) Self-as-context — the observing self, a stable perspective from which inner experiences can be witnessed without fusion; (5) Values — identifying freely chosen life directions that give action meaning; (6) Committed action — taking concrete, values-consistent steps even in the presence of difficult feelings.

Experiential avoidance is the attempt to suppress, escape, or avoid unwanted inner experiences — thoughts, feelings, memories, physical sensations — even when doing so is costly or unhelpful. ACT views experiential avoidance as the central process maintaining psychopathology: attempts at thought suppression paradoxically increase intrusion (the ironic rebound effect), and organising life around avoidance progressively narrows the person's behavioural repertoire. ACT targets experiential avoidance not by eliminating it but by reducing its grip on behaviour, so clients can act in accordance with values even when avoidance impulses are present.

ACT has accumulated a substantial evidence base since the first randomised controlled trials in the 1980s. A-Tjak et al.'s 2015 meta-analysis of 39 RCTs found ACT superior to waitlist/TAU and statistically equivalent to CBT for anxiety and depression. Hayes et al.'s 2006 meta-analysis found ACT superior to controls across diverse presentations. ACT is supported for anxiety disorders, depression, chronic pain, substance use, OCD spectrum, and workplace stress. It is particularly valuable when control-based strategies have already been tried and have not produced lasting change.