At the core of collusions are unconscious unresolved issues shared by two or more participants, interlocked in a defensive maneuver. The issue at stake is avoided at an intrapsychic level and externalized in the interpersonal space. Unresolved issues may pertain to control, intimacy, loss, dependency, domination, boundaries and so on.This critical narrative review is based on a comprehensive consultation of the psychoanalytic, general system theory, family therapy and social psychology literature and is informed by our experience as psychotherapists, supervisors, and researchers. When working with the concept of collusion, be it as a clinician, supervisor or researcher, collusions must be delineated from other group dynamics. This might not always be easy. Moreover, reports on polyadic collusions and their contextual determinants are scattered in the literature of different psychotherapeutic approaches and lack precision at times. We therefore engage in a critical dialog with the literature and define different types of polyadic collusions, helping the reader gain a quick overview of this somehow neglected concept. Collusions occur in the psychiatric, psychotherapeutic, and medical setting, but especially in settings which ignore the unconscious and the impact of the wider social determinants on collusions.Collusion is a very useful concept since it brings together different therapeutic orientations but also patients and clinicians, the personal and professional of the caregiver, as well as psychotherapy, psychiatry, medicine, and the social sciences.
