A patient describes an unusual experience of self. Before revealing the answer, decide what distinguishes the experience of multiple personalities from a disturbance of self-unity.

Ask whether the person retains a qualifying sense that this is not literally true, and whether the experience involves genuinely distinct, separately characterised personalities. The experience of multiple personalities differs from disturbance of self-unity, in which a person feels like two people at a single moment, often with retained 'as if' insight, whereas this involves distinct, separately experienced personalities, often without that qualification. Disturbance of self-unity typically involves feeling like more than one person at a single moment, often described as acting automatically as though driven by another part of oneself, most commonly with the qualifying sense that this is 'as if' rather than literal. The experience of multiple personalities goes further, involving genuinely distinct, separately characterised personalities without necessarily that same qualifying insight, and represents the most severe and specific form within this family of disturbance. The presence of fully distinct personalities, and the loss of the qualifying 'as if' insight, is the key distinguishing feature.