Reciprocal Contributions Between Functional Analytic Psychotherapy (FAP) and Acceptance and Commitment Therapy (ACT)

Abstract Functional Analytic Psychotherapy (FAP) and Acceptance and Commitment Therapy (ACT) are representative approaches of contextual therapies and, at the same time, belong to Contextual Behavioral Science (CBS). Although the two share behavioral roots, they are based on distinct philosophical traditions: FAP is based on radical behaviorism, while ACT is developed from functional contextualism. These differences generate tensions in the conceptualization of the client, language, and therapeutic change, which have rarely been discussed critically. However, their integration is promising: FAP provides tools to intervene in clinically relevant interpersonal patterns, while ACT offers strategies to address intrapersonal processes from a perspective of psychological flexibility. This theoretical article seeks to explore the integration of FAP and ACT, highlighting both the potential and limitations of this combined approach. Finally, directions for future research and recommendations for therapist training are proposed.