This particular kind of institutional, asymmetric practitioner-client talk, which may well get personal and affective, aims at improving the client's mental health. Conversation analysis (CA) reveals, how an interplay of comprehension of both content of talk and relation to the co-participant, forwards the therapeutic process. The described actions -i.e. therapists' formulations, interpretations and extensions, and clients' (dis)agreement to them -are interactional means for the interplay of understanding and the momentary therapist-client relationship (Peräkylä 2012). Recently, scholars have started to examine (besides "within session") "across sessions" interactional processes, and comparatively within different psychotherapy types. Future research will include constant research on the sequential organization of action in psychotherapy, though this is so multilateral and variable by approach, clinician and client, that a single global psychotherapeutic interaction model is not to be expected.