The term dissociation has been part of the psychological lexicon for over a century. Pierre Janet could be considered the father of the phenomenon of dissociation. His work, beginning in 1887, laid the foundation for our present day understanding of the phenomenon of dissociation. Janet hypothesized that consciousness is comprised of various levels, some of which can be held outside of awareness.
As the word implies, dissociation involves a disconnection of that which is normally associated. As a psychological phenomenon, it refers to a disconnection of some dimensions of experience from the mainstream of conscious awareness.
The phenomenon of dissociation exists on a continuum. In very mild forms it occurs in everyday life such as when we miss an exit on the highway because we were daydreaming or when we absent mindedly mislay our keys because we were attending to something else as we put them down. In these instances we are acting without conscious awareness or, put slightly differently, our actions are disconnected from our conscious awareness. At the other end of the spectrum, dissociation can involve entire personalities with independent, disconnected sets of memories co-existing within a single body without awareness of the other(s) as in the case with dissociative identity disorder. Somewhere in between these two ends of the continuum is a range of dissociative experiences and phenomena.
Dissociative processes are often a response to anxiety or trauma. As a defense against something intolerable, the the mind segregates from ordinary consciousness experiences which are too difficult to bear. Dissociation has been described as an attempt of the mind to flee what the body cannot escape. Dissociation as a response to unbearable stress has adaptive value because it serves to moderate the degree of stimulation a person experiences so as to make organized coping possible. In this sense, dissociative processes can thus be thought of as adaptive responses to aversive or traumatic situations.
The primary characteristic of dissociative processes is a detachment from reality. This is in contrast with a loss of reality as in the case of psychosis. There are three main types of dissociative behavior including amnesia, absorption, and depersonalization. Dissociative amnesia involves finding oneself in situations wherein you have performed actions of which you have no memory. Dissociative absorption involves becoming so involved in an activity that you are unaware of what is going on around you. Dissociative depersonalization is the experience of events as if you are an observer who is disconnected from your body or feelings.
How is dissociation treated? It is generally treated in phases as is the case with other trauma related disorders. The primary focus of treatment is the integration of the dissociated experiences once there is sufficient safety in the therapeutic context. The goal is for a person to be able to tolerate (without autonomic nervous system hyper or hypo arousal) integrating the dissociated experiences while remaining grounded in the present rather than reliving the experience as though it were happening again. Integration involves developing an awareness of reality of the past and the present as it is, accepting it, and reflectively adapting to it.