{{Short description|Thought disorder in psychiatry}} {{Expand language|topic=|langcode=De|otherarticle=Derailment|date=April 2026}} In psychiatry, '''derailment''' (aka '''loosening of association''', '''asyndesis''', '''asyndetic thinking''', '''knight's move thinking''', '''entgleisen''', '''disorganised thinking'''<ref name=ICD-11>World Health Organization (2023). "{{ICD11|MB25.02|1746204479}} Disorganised thinking". ''International Classification of Diseases, eleventh revision – ICD-11''. Genova – [https://icd.who.int icd.who.int].</ref>) categorises any speech comprising sequences of unrelated or barely related ideas; the topic often changes from one sentence to another.<ref name=textbook>{{cite book|author=P.J. McKenna|title=Schizophrenia and related syndromes|publisher=Psychology Press|year=1997|isbn=0-86377-790-2|pages=14–15}}</ref><ref name=sims>A.C.P. Sims, ''Symptoms in the mind: an introduction to descriptive psychopathology'', Edition 3, Elsevier Health Sciences, 2003, {{ISBN|0-7020-2627-1}}, pp. 155-156</ref><ref name=ICD-11 />
==Disorder== In a mild manifestation, this thought disorder is characterized by slippage of ideas further and further from the point of a discussion. Derailment can often be manifestly caused by intense emotions such as euphoria or hysteria. 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.<ref name=textbook/> In some studies on creativity, ''knight's move thinking''—while describing a similarly loose association of ideas—is not considered a mental disorder or the hallmark of one; it is sometimes used as a synonym for lateral thinking.<ref name=pp/><ref>Tudor Rickards, ''Creativity and problem solving at work'', Edition 3, Gower Publishing, 1997, {{ISBN|0-566-07961-5}}, p. 81</ref><ref>Richard Courtney, ''Drama and intelligence: a cognitive theory'', McGill-Queen's Press, 1990, {{ISBN|0-7735-0766-3}}, p. 128</ref>
== 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<ref>{{cite journal |url=http://archpsyc.ama-assn.org/cgi/content/abstract/36/12/1315 |title=Thought, Language, and Communication Disorders: I. Clinical Assessment, Definition of Terms, and Evaluation of Their Reliability |journal=Archives of General Psychiatry |date=November 1979 |volume=36 |issue=12 |pages=1315–1321 |doi=10.1001/archpsyc.1979.01780120045006 |accessdate=2010-05-05 |url-status=live |archiveurl=https://web.archive.org/web/20100315030254/http://archpsyc.ama-assn.org/cgi/content/abstract/36/12/1315 |archivedate=2010-03-15 |last1=Andreasen |first1=Nancy C. |pmid=496551 |url-access=subscription }}</ref> * "I think someone's infiltrated my copies of the cases. We've got to case the joint. I don't believe in joints, but they do hold your body together."—given by Elyn Saks.<ref>Elyn Saks: "A tale of mental illness — from the inside." TEDGlobal 2012. Recorded in June 2012. {{cite web |url=https://www.ted.com/talks/elyn_saks_a_tale_of_mental_illness_from_the_inside |title=A tale of mental illness -- from the inside |date=29 June 2012 |access-date=2014-03-26 |url-status=live |archive-url=https://web.archive.org/web/20140326103904/http://www.ted.com/talks/elyn_saks_seeing_mental_illness |archive-date=2014-03-26 }}</ref>
== History == {{lang|de|Entgleisen}} (derailment in German) was first used with this meaning by Carl Schneider in 1930.<ref name=sims/> The term ''asyndesis'' was introduced by N. Cameron in 1938, while ''loosening of association'' was introduced by A. Bleuler<!--not Eugen, that guy was dead by then--> in 1950.<ref name=lyttle>Tony Thompson, Peter Mathias, Jack Lyttle, ''Lyttle's mental health and disorder'', Edition 3, Elsevier Health Sciences, 2000, {{ISBN|0-7020-2449-X}}, pp. 136, 168-170</ref> 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 individuals with schizophrenia fail to suppress divergent associations.<ref name=pp>Robert Spillane, John Martin, ''Personality and performance: foundations for managerial psychology'', UNSW Press, 2005 {{ISBN|0-86840-816-6}}, pp. 239-243</ref> ''Derailment'' was used with this meaning by Kurt Schneider in 1959.<ref name=lyttle/>
==See also== * Nonsense * Non sequitur (logic) and non sequitur (literary device) * Red herring * Relevance logic * Schizophasia * SCIgen, a program that generates nonsense research papers by grammatically combining snippets; many of the sentences generated are individually plausible * Tip-of-the-tongue * Train of thought
==References== {{reflist|30em}}
{{DEFAULTSORT:Derailment}} Category:Cognition Category:Medical signs Category:Thought disorders