In psychiatry, thought disorder or formal thought disorder is a term used to describe a symptom of psychotic mental illness. Psychiatry is the branch of medicine that studies, diagnoses and treats mental illness and behavioral disorders. ... This article is about the mental state. ... The Scream, the famous painting commonly thought of as depicting the experience of mental illness. ...

It describes a persistent underlying disturbance to conscious thought and is classified largely by its effects on speech and writing. Affected persons may show pressure of speech (speaking incessantly and quickly), derailment or flight of ideas (switching topic mid-sentence or inappropriately), thought blocking, rhyming, punning, or 'word salad' when individual words may be intact but speech is incoherent. One might be looking for the academic discipline of communications. ... Writing may refer to two activities: the inscribing of characters on a medium, with the intention of forming words and other constructs that represent language or record information, and the creation of material to be conveyed through written language. ... A rhyme is a repetition of identical or similar sounds in two or more different words and is most often used in poetry. ... A pun (also known as paronomasia) is a figure of speech which consists of a deliberate confusion of similar words or phrases for rhetorical effect, whether humorous or serious. ... In the mental health field, word salad (originally from the German Wortsalat) is used to describe the symptom of confused, and often repetitious, language that is symptomatic of various mental illnesses. ...

Subtypes in detail

Nancy Andreasen^[1] has given the following definitions.

• Pressure of speech - An increase in the amount of spontaneous speech compared to what is considered customary.
• Distractible speech - During mid speech, the subject is changed in response to a stimulus. e.g. "Then I left San Francisco and moved to... where did you get that tie ?"
• Tangentiality - Replying to questions in an oblique, tangential or irrelevant manner. e.g. "What city are you from ?", "Well, that's a hard question. I'm from Iowa. I really don't know where my relatives came from, so I don't know if I'm Irish or French".
• Derailment - Ideas slip off the track on to another which is obliquely related or unrelated. e.g. "The next day when I'd be going out you know, I took control, like uh, I put bleach on my hair in California".
• Incoherence (word salad) - Speech that is unintelligible due to the fact that, though the individual words are real words, the manner in which they are strung together results in incoherent gibberish, e.g. the question "Why do people believe in God?" elicits a response like "Because make a twirl in life, my box is broken help me blue elephant. Isn't lettuce brave? I like electrons, hello."
• Illogicality - Conclusions are reached that do not follow logically (non sequiturs or faulty inductive inferences).
• Clanging - Sounds rather than meaningful relationships appear to govern words. e.g. "I'm not trying to make noise. I'm trying to make sense. If you can't make sense out of nonsense, well, have fun".
• Neologisms - New word formations. e.g. "I got so angry I picked up a dish and threw it at the geshinker".
• Word approximations - Old words used in a new and unconventional way. e.g. "His boss was a seeover".
• Circumstantiality - Speech that is very delayed at reaching its goal. Excessive long windedness.
• Loss of goal - Failure to show a chain of thought to a natural conclusion.
• Perseveration - Persistent repetition of words or ideas. e.g. "I'll think I'll put on my hat, my hat, my hat, my hat, my hat, my hat, my hat, my hat..."
• Echolalia - Echoing of other people's speech e.g. "Can we talk for a few minutes?", "Talk for a few minutes".
• Blocking - Interruption of train of speech before completed.
• Stilted speech - Speech excessively stilted and formal. e.g. "The attorney comported himself indecorously".
• Self-reference - Patient repeatedly and inappropriately refers back to self. e.g. "What's the time?", "It's 7 o'clock. That's my problem".
• Phonemic paraphasia - Mispronunciation; syllables out of sequence. e.g. "I slipped on the lice broke my arm".
• Semantic paraphasia - Substitution of inappropriate word. e.g. "I slipped on the coat, on the ice I mean, and broke my book".

Diagnostic issues

The concept of thought disorder has been criticised as being based on circular or incoherent definitions^[2]. For example, thought disorder is inferred from disordered speech, however it is assumed that disordered speech arises because of disordered thought. Similarly the definition of 'Incoherence' (word salad) is that speech is incoherent.

References

1. ^  Andreasen NC. Thought, language, and communication disorders. I. Clinical assessment, definition of terms, and evaluation of their reliability. Archives of General Psychiatry 1979;36(12):1315-21. PMID 496551.
2. ^  Bentall, R. (2003) Madness explained: Psychosis and Human Nature. London: Penguin Books Ltd. ISBN 0713992492

Richard Bentall (1956 -) is a Chair in Experimental Clinical psychology at the University of Manchester, UK. Born in Sheffield, he attended the University College of North Wales, Bangor as an undergraduate before taking a Ph. ...

See also

• Psychosis
• Schizophrenia

This article is about the mental state. ...

Further reading

• Sims, A. (1995) Symptoms in the mind: An introduction to descriptive psychopathology. Edinburgh: Elsevier Science Ltd. ISBN 0702026271