Acceptance and Commitment Therapy (ACT)
A behavioural psychotherapy co-developed by steven-hayes, built from mindfulness, acceptance, and values-based methods. Rather than disputing distressing thoughts for accuracy — the cognitive-therapy move — ACT works on a person’s relationship to them, and pairs that with committed action toward stated values. Its trade-press statement is a-liberated-mind (2019).
The wiki now holds the tradition ACT departed from. Both descend from aaron-beck‘s break with psychoanalysis and both are testable by construction; they prescribe opposite operations on the same object — correct the thought, or change your relationship to it. That disagreement is live in synthesis and neither side is settled here.
Underneath it sits Relational Frame Theory, Hayes’s separate account of human higher cognition, tested in roughly 300 studies. RFT is the theoretical claim about why language and thought entangle people in their own suffering; ACT is the clinical programme built on it. That a therapy ships with an explicit theory of the mechanism it exploits is unusual on this spoke — the interpretive traditions supply a mechanism story too (analytical-psychology), but not one anybody tried to test separately.
The evidence base, and what this spoke can say about it
Over 900 randomized controlled trials. The World Health Organization distributes ACT-based stress-management resources internationally; the American Psychological Association and the US Department of Veterans Affairs both list it as empirically supported.
That makes ACT the most heavily trialled thing in this wiki by a wide margin, and it breaks the founding assumption that clinical work sits at the untestable end of the method spectrum. It does not, by itself, settle whether ACT works better than its alternatives. Psychotherapy trials carry known problems this corpus has flagged elsewhere (replication-crisis) — allegiance effects, small samples, active-control choice — and the spoke holds no source assessing the quality of those 900. The count is recorded as a count. See a-liberated-mind for the provenance limitation behind it.
Related
steven-hayes · a-liberated-mind · cognitive-behavioral-therapy · existential-psychotherapy · replication-crisis · flow · synthesis