is a contextual therapy that is part of the so-called third generation therapies (Hayes, 2004; Pérez-Alvarez, 2012). One key feature is to reconsider the therapeutic context itself as the fundamental interaction for a change in behaviour to occur. The functional analysis of the therapeutic relationship is proposed as fundamental as it assumes that the clinical setting is a natural condition where a client's problems may occur, and also an opportunity for the client to make improvements. FAP is an idiographic therapy, which is based on the principles of functional analysis of a client's behaviour during the session. It includes contingencies of natural reinforcement and shaping that happen within the clinical session itself. In addition, FAP establishes the functional equivalence of the behaviour in the context of a session with other outside behaviours, which occur during the daily life of an individual (Kohlenberg & Tsai, 1991, 1995). The change process focuses on a client's direct behaviour, what the client does and/or says within the session (including talking, thinking, feeling, seeing, hearing, remembering, emotional responses, etc.), which are the so-called "clinically relevant behaviours" (CRB). There are three types of these behaviours, which the therapist must learn to identify as therapeutic goals (Kohlenberg & Tsai, 1991, 1994, 1995; Kohlenberg et al., 2009). CRB type 1 are the client's problems that are revealed during the session, usually complaints and problems that cause him/her to suffer, and whose frequency should Clínica y Salud (2021) xx(x) xx-xx