Abstract
BACKGROUND: Acceptance and commitment therapy (ACT) is a third-generation therapy that appears to be a promising psychological intervention for psychotic disorders. While several systematic reviews and meta-analyses that address the efficacy of ACT for psychosis have been conducted, no systematic review has specifically focused on the application of ACT to the early stages of psychosis. AIM: To review the state of the art regarding the feasibility and efficacy of treating early psychosis (EP) with ACT-based interventions. METHODS: First, we describe the foundations of the ACT model to provide the background required to contextualize the main objective of this review. Second, we searched the PubMed and PsycINFO databases for studies published up to January 2025 and identified eight studies that met our selection criteria. The systematic review was conducted in accordance with the PRISMA guidelines and the critical appraisal checklist provided by the Joanna Briggs Institute for randomized controlled trials (RCTs). RESULTS: All studies were published after 2019. Among the reviewed studies, five were RCTs with a total combined sample of 399 nonoverlapping participants. The methodological quality was moderate for RCTs. The results showed that ACT-based treatments are feasible and improve psychotic symptoms, medication adherence, and global functioning in patients with EP. Furthermore, preliminary evidence exists for the benefits of group-based and online-delivered programs and those that combine face-to-face therapy with novel real-time digital interventions, such as "ecological momentary intervention", to apply therapeutic concepts to real life. CONCLUSION: ACT-based treatments in the early stages of psychosis are feasible and improve symptoms, treatment adherence, and self-care skills. Although promising, these results are inconclusive. Further research is required.