Derailment (thought disorder)

In psychiatry, derailment (also loosening of association, asyndesis, asyndetic thinking, knight's move thinking, or entgleisen) refers to a pattern of discourse (in speech or writing) that is a sequence of unrelated or only remotely related ideas. The frame of reference often changes from one sentence to the next.^[1][2] Examples:

• "The next day when I'd be going out you know, I took control, like uh, I put bleach on my hair in California."—given by Nancy C. Andreasen^[3]
• "The traffic is rumbling along the main road. They are going to the north. Why do girls always play pantomime heroes."—given by Carl Schneider^[2]

In a mild manifestation, this thought disorder is characterized by slippage of ideas further and further from the point of a discussion. Some of the synonyms given above (loosening of association, asyndetic thinking) are used by some authors to refer just to a loss of goal: discourse that sets off on a particular idea, wanders off and never returns to it. A related term is tangentiality—it refers to off-the-point, oblique or irrelevant answers given to questions.^[1]

Entgleisen (derailment in German) was first used with this meaning by Carl Schneider in 1930.^[2] The term asyndesis was introduced by N. Cameron in 1938, while loosening of association was introduced by A. Bleuler in 1950.^[4] The phrase knight's move thinking was first used in the context of pathological thinking by the psychologist Peter McKellar in 1957, who hypothesized that schizophrenics fail to suppress divergent associations.^[5] In some studies on creativity, knight's move thinking, while it describes a similarly loose association of ideas, it is not considered a mental disorder or the hallmark of one; it is sometimes used as a synonym for lateral thinking.^[5][6][7] Derailment was used with this meaning by Kurt Schneider in 1959.^[4]

See also

• Train of thought
• Non sequitur (logic) and Non sequitur (literary device)
• Nonsense
• SCIgen, a program that generates nonsense research papers by grammatically combining snippets; many of the sentences generated are individually plausible
• Relevance logic
• Tip-of-the-tongue

References

1. ^ ^{a b} P.J. McKenna, Schizophrenia and related syndromes, Psychology Press, 1997, ISBN 0863777902, pp. 14-15
2. ^ ^{a b c} A.C.P. Sims, Symptoms in the mind: an introduction to descriptive psychopathology, Edition 3, Elsevier Health Sciences, 2003, ISBN 0702026271, pp. 155-156
3. ^ Andreasen NC. Thought, language, and communication disorders. I. A Clinical assessment, definition of terms, and evaluation of their reliability. Archives of General Psychiatry 1979;36(12):1315-21. PMID 496551. [1]
4. ^ ^{a b} Tony Thompson, Peter Mathias, Jack Lyttle, Lyttle's mental health and disorder, Edition 3, Elsevier Health Sciences, 2000, ISBN 070202449X, pp. 136, 168-170
5. ^ ^{a b} Robert Spillane, John Martin, Personality and performance: foundations for managerial psychology, UNSW Press, 2005 ISBN 0868408166, pp. 239-243
6. ^ Tudor Rickards, Creativity and problem solving at work, Edition 3, Gower Publishing, 1997, ISBN 0566079615, p. 81
7. ^ Richard Courtney, Drama and intelligence: a cognitive theory, McGill-Queen's Press, 1990, ISBN 0773507663, p. 128