In psychoanalysis, a defence mechanism in which emotion is detached from an idea and rendered unconscious, leaving the idea bland and emotionally flat. It is especially important in obsessive-compulsive disorder, and in non-disordered people it most often occurs following a traumatic experience. The mechanisms by which the detachment is effected include repetitive intrusive thoughts and ritualistic behaviour. Sigmund Freud (1856–1939) expressed his ideas about isolation most clearly in his book Inhibitions, Symptoms and Anxiety (1926, Standard Edition, XX, pp. 77–175, at pp. 120–2). Also called isolation. See also decathexis.