It has been claimed that the progress of psychiatry has lagged behind that of other medical disciplines over the last few decades. This may suggest the need for innovative thinking and research in psychiatry, which should consider neglected areas as topics of interest in light of the potential progress which might be made in this regard. This review is concerned with one such field of psychiatry: dissociation and dissociative disorders. Dissociation is the ultimate form of human response to chronic developmental stress, because patients with dissociative disorders report the highest frequency of childhood abuse and/or neglect among all psychiatric disorders. The cardinal feature of dissociation is a disruption in one or more mental functions. Dissociative amnesia, depersonalization, derealization, identity confusion, and identity alterations are core phenomena of dissociative psychopathology which constitute a single dimension characterized by a spectrum of severity. While dissociative identity disorder (DID) is the most pervasive condition of all dissociative disorders, partial representations of this spectrum may be diagnosed as dissociative amnesia (with or without fugue), depersonalization disorder, and other specified dissociative disorders such as subthreshold DID, dissociative trance disorder, acute dissociative disorders, and identity disturbances due to exposure to oppression. In addition to constituting disorders in their own right, dissociation may accompany almost every psychiatric disorder and operate as a confounding factor in general psychiatry, including neurobiological and psycho-pharmacological research. While an anti-dissociative drug does not yet exist, appropriate psychotherapy leads to considerable improvement for many patients with dissociative disorders.

This review aims to clarify the use of the term ‘dissociation’ in theory, research and clinical practice. Current psychiatric definitions of dissociation are contrasted with recent conceptualizations that have converged on a dichotomy between two qualitatively different phenomena: ‘detachment’ and ‘compartmentalization’. We review some evidence for this distinction within the domains of phenomenology, factor analysis of self-report scales and experimental research. Available evidence supports the distinction but more controlled evaluations are needed. We conclude with recommendations for future research and clinical practice, proposing that using this dichotomy can lead to clearer case formulation and an improved choice of treatment strategy. Examples are provided within Depersonalization Disorder, Conversion Disorder and Posttraumatic Stress Disorder (PTSD).

"Controversy about dissociation and the dissociative disorders (DD) has existed since the beginning of modern psychiatry and psychology. Even among professionals, beliefs about dissociation/DD often are not based on the scientific literature. Multiple lines of evidence support a powerful relationship between dissociation/DD and psychological trauma, especially cumulative and/ or early life trauma. Skeptics counter that dissociation produces fantasies of trauma, and that DD are artefactual conditions produced by iatrogenesis and/or socio-cultural factors. Almost no research or clinical data support this view" (page 229, Loewenstein, R. (2018). Dissociation debates: everything you know is wrong. Dialogues in Clinical Neuroscience , 20 (3): 229-242. Available at: www.dialogues-cns.org. (Dr K Johansson Blight is not an author of this article but recommend its reading).