In considering whether an individual has Thought Disorder, patterns of their speech are closely observed. Although it is normal to exhibit some of the following during times of extreme stress (e.g. a cataclysmic event or the middle of a war) it is the degree, frequency, and the resulting functional impairment that leads to the conclusion that the person being observed has a thought disorder.
Alogia (also Poverty of Speech) - Deficiency in content of speech compared to what level of information is normally expected. e.g. in an informal conversation, "Do you have any siblings?" "Yes."
Blocking – Interruption of train of speech before completion. e.g. "Am I early?" "No, you're just about on..."(silence) At an extreme degree, after blocking occurs, the speaker does not recall the topic he or she was discussing. True blocking is a common sign of schizophrenia.
Circumstantiality – Speech that is highly detailed and very delayed at reaching its goal. Speaking about many concepts related to the point of the conversation before eventually returning to the point and concluding the thought.
Excessive long-windedness. e.g. "What is your name?" "Well, sometimes when people ask me that I have to think about whether or not I will answer because some people think it's an odd name even though I don't really because my mum gave it to me and I think my dad helped but it's as good a name as any in my opinion, I think it's a little weird to have the same name as two of my other names, but the fact that I like it is a good thing... but yeah, it's Gordon."
Clanging – Sounds, rather than meaningful relationships, appear to govern words or topics. Excessive rhyming, and/or alliteration. e.g. "Many moldy mushrooms merge out of the mildewy mud on Mondays." "I heard the bell. Well, hell, then I fell."
Derailment (also Loose Association and Knight's Move Thinking) – Ideas slip off the topic's 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."
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?"
Echolalia – Echoing of one's or other people's speech that may only be committed once, or may be continuous in repetition. This may involve repeating only the last few words or last word of the examiner's sentences. This can be a symptom of Tourette's Syndrome. e.g. "What would you like for dinner?", "That's a good question. That's a good question. That's a good question. That's a good question."
Evasive interaction – Attempts to express ideas and/or feelings about another individual come out as evasive or in a diluted form, e.g.: "I... er ah... you are uh... I think you have... uh-- acceptable erm... uh... hair."
Flight of ideas – A sequence of loose associations or extreme tangentiality where the speaker goes quickly from one idea to another seemingly unrelated idea. To the listener, the ideas seem unrelated and do not seem to repeat. Often pressured speech is also present. e.g. "I own five cigars. I've been to Havana. She rose out of the water, in a bikini."
Illogicality – Conclusions are reached that do not follow logically (non-sequiturs or faulty inferences). e.g. "Do you think this will fit in the box?" draws a reply like "Well duh; it's brown, isn't it?"
Incoherence (Word Salad) – Speech that is unintelligible because, 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 comb their hair?" elicits a response like "Because it makes a twirl in life, my box is broken help me blue elephant. Isn't lettuce brave? I like electrons, hello please!"
Loss of goal – Failure to follow a train of thought to a natural conclusion. e.g. "Why does my computer keep crashing?", "Well, you live in a stucco house, so the pair of scissors needs to be in another drawer."
Neologisms – New word formations. These may also involve elisions of two words that are similar in meaning or in sound. e.g. "I got so angry I picked up a dish and threw it at the geshinker."
Perseveration – Persistent repetition of words or ideas. e.g. "It's great to be here in Nevada, Nevada, Nevada, Nevada, Nevada." This may also involve repeatedly giving the same answer to different questions. e.g. "Is your name Mary?" "Yes." "Are you in the hospital?" "Yes." "Are you a table?" "Yes." Perseveration can include palilalia and logoclonia and is often an indication of organic brain disease such as Parkinson's.
Phonemic paraphasia – Mispronunciation; syllables out of sequence. e.g. "I slipped on the lice and broke my arm."
Pressure of speech – An increase in the amount of spontaneous speech compared to what is considered customary. This may also include an increase in the rate of speech. Alternatively it may be difficult to interrupt the speaker; the speaker may continue speaking even when a direct question is asked.
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."
Semantic paraphasia – Substitution of inappropriate word. e.g. "I slipped on the coat, on the ice I mean, and broke my book."
Stilted speech – Speech excessively stilted and formal. e.g. "The attorney comported himself indecorously."
Tangentiality – Replying to questions in an oblique, tangential or irrelevant manner. e.g.:
Q: "What city are you from?"
A: "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."
Word approximations – Old words used in a new and unconventional way. e.g. "His boss was a seeover."