Circumstantial speech (also referred to as circumstantiality) is the result of a so called "non-linear thought pattern" and occurs when the focus of a conversation drifts, but often comes back to the point. In circumstantiality, apparently unnecessary details and seemingly irrelevant remarks cause a delay in getting to the point.

If someone exhibits circumstantial speech during a conversation, they will often seem to "talk the long way around" to their point, which may be an attempt by the speaker to include pertinent hyperspatial details, that may contrast with linear speech, which is more direct, succinct, and to the point (the gist) even at the expense of more precise, accurate communication. Some individuals with autistic tendencies may prefer highly precise speech, and this may seem circumstantial, but in fact it is a choice that posits that more details are necessary to communicate a precise meaning, and preempt more disastrous ambiguous communication.

Circumstantial speech is more direct than tangential speech in which the speaker wanders and drifts (in order to add more thought vectors in unrelated hyperplanes) and usually never returns to the original topic, and is far less severe than logorrhea. A helpful metaphor is traveling to a destination. If someone is thinking and speaking linearly, then they will go directly to the point. Circumstantial speech is more like taking "unnecessary" detours, according to some, but the speaker eventually arrives at the intended destination. In tangential speech, the speaker simply gets lost along the way, never returning to the original topic of conversation. With logorrhea, which is closer to word salad, it may not even be clear that the speaker had a particular idea or point in the first place.

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") – A poverty of speech, either in amount or content; it can occur as a negative symptom of schizophrenia.

- "Blocking" – An abrupt stop in the middle of a train of thought; the individual may or may not be able to continue the idea. This is a type of formal thought disorder that can be seen in schizophrenia.

- "Circumstantiality" (also "circumstantial thinking", or "circumstantial speech") – An inability to answer a question without giving excessive, unnecessary detail. This differs from tangential thinking, in that the person does eventually return to the original point.

- "Clanging" or "Clang association" – a severe form of flight of ideas whereby ideas are related only by similar or rhyming sounds rather than actual meaning. This may be heard as 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." It is most commonly seen in bipolar affective disorder (manic phase), although it is often observed in patients with primary psychoses, namely schizophrenia and schizoaffective disorder.

- "Derailment" (also "loose association" and "knight's move thinking") – Thought and/or speech move, either spontaneously or in response to an internal stimulus (distinguishing derailment from "distractible speech," "infra"), from the topic's track onto 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 an external stimulus. e.g. "Then I left San Francisco and moved to... where did you get that tie?"

- "Echolalia" – Echoing of another'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 form of formal thought disorder marked by abrupt leaps from one topic to another, albeit with discernable links between successive ideas, perhaps governed by similarities between subjects or, in somewhat higher grades, by rhyming, puns, and word plays (clang associations), or innocuous environmental stimuli – e.g., the sound of birds chirping. It is most characteristic of the manic phase of bipolar illness.

- "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 even when another person attempts to change the topic. 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 can be 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" – Unrelenting, rapid speech without pauses. It may be difficult to interrupt the speaker, and 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 characterized by the use of words or phrases that are flowery, excessive, and pompous. e.g. "The attorney comported himself indecorously."

- "Tangentiality" – Wandering from the topic and never returning to it or providing the information requested. e.g. in answer to the question "Where are you from?", a response "My dog is from England. They have good fish and chips there. Fish breathe through gills."

- "Word approximations" – Old words used in a new and unconventional way. e.g. "His boss was a ."

A person afflicted with circumstantiality has slowed thinking and invariably talks at length about irrelevant and trivial details (i.e. circumstances). Eliciting information from such a person can be difficult since circumstantiality makes it hard for the individual to stay on topic. In most instances however, the relevant details are eventually achieved.

The disorder is often associated with schizophrenia and obsessive-compulsive disorder.

The concept of thought disorder has been criticized as being based on circular or incoherent definitions. For example, thought disorder is inferred from disordered speech, based on the assumption that disordered speech arises because of disordered thought. Incoherence, or word salad, refers to speech that is unconnected and conveys no meaning to the listener.

Furthermore, although thought disorder is typically associated with psychosis, similar phenomena can appear in different disorders, potentially leading to misdiagnosis—for example, in the case of incomplete yet potentially fruitful thought processes.

It has been suggested that individuals with autism spectrum disorders (ASD) display language disturbances like those found in schizophrenia; a 2008 study found that children and adolescents with ASD showed significantly more illogical thinking and loose associations than control subjects. The illogical thinking was related to cognitive functioning and executive control; the loose associations were related to communication symptoms and to parent reports of stress and anxiety.

Some individuals may exhibit hyperreligiosity, characterized by increased, usually intense, religious feelings and philosophical interests, and partial (temporal lobe) epilepsy patients with frequent numinous-like auras have greater ictal and interictal spirituality. Some auras include ecstatic experiences. It has been reported that many religious leaders exhibit this form of epilepsy. These religious feelings can motivate beliefs within any religion, including Voodoo, Christianity, Islam, and others. Furthermore, in Geschwind syndrome, "in someone from a strongly religious background hyperreligiosity might appear as deeply felt atheism". There are reports of patients converting between religions. A few patients internalize their religious feelings: when asked if they are religious they say they are not. One reviewer concluded that the evidence for a link between temporal lobe epilepsy and hyperreligiosity "isn't terribly compelling".

Hypergraphia is the tendency for extensive and compulsive writing or drawing, and has been observed in persons with temporal lobe epilepsy who have experienced multiple seizures. Those with hypergraphia display extreme attention to detail in their writing. Some such patients keep diaries recording meticulous details about their everyday lives. In certain cases, these writings demonstrate extreme interest in religious topics. Also, these individuals tend to have poor penmanship. The novelist Fyodor Dostoyevsky showed symptoms of Geschwind syndrome, including hypergraphia. In some cases hypergraphia can manifest with compulsive drawing. Drawings by patients with hypergraphia exhibit repetition and a high level of detail, sometimes morphing writing with drawing

Focal impaired awareness seizures are seizures which impair consciousness to some extent: they alter the person's ability to interact normally with their environment. They usually begin with a focal aware seizure, then spread to a larger portion of the temporal lobe, resulting in impaired consciousness. They may include autonomic and psychic features present in focal aware seizures.

Signs may include:

- Motionless staring

- Automatic movements of the hands or mouth

- Confusion and disorientation

- Altered ability to respond to others, unusual speech

- Transient aphasia (losing ability to speak, read, or comprehend spoken word)

These seizures tend to have a warning or aura before they occur, and when they occur they generally tend to last only 1–2 minutes. It is not uncommon for an individual to be tired or confused for up to 15 minutes after a seizure has occurred, although postictal confusion can last for hours or even days. Though they may not seem harmful, due to the fact that the individual does not normally seize, they can be extremely harmful if the individual is left alone around dangerous objects. For example, if a person with complex partial seizures is driving alone, this can cause them to run into the ditch, or worse, cause an accident involving multiple people. With this type, some people do not even realize they are having a seizure and most of the time their memory from right before or after the seizure is wiped. First-aid is only required if there has been an injury or if this is the first time a person has had a seizure.

Other medical conditions with similar symptoms include panic attacks, psychosis spectrum disorders, tardive dyskinesia, and occipital lobe epilepsy.

Delirious patients have diminished comprehension as evidenced by reduced ‘grasp’ of their surroundings and difficulties in connecting with their immediate environment, executive dysfunction affecting abstraction, initiation/perseveration, switching mental sets, working memory, temporal sequencing and organization, insight and judgment. Though none of these cognitive deficits is specific to delirium, the array and pattern is highly suggestive.

Language disturbances in delirium include anomic aphasia, paraphasias, impaired comprehension, agraphia, and word-finding difficulties. Incoherent or illogical / rambling conversation is reported commonly. Disorganised thinking includes tangentiality, circumstantiality and a proneness to loose associations between elements of thought which results in speech that often makes limited sense with multiple apparent irrelevancies. This aspect of delirium is common but often difficult for non-experts to assess reliably.

Disruption of sleep-wake cycle is almost invariably present in delirium and often predates the appearance of a full-blown episode. Minor disturbances with insomnia or excessive daytime somnolence may be hard to distinguish from other medically ill patients without delirium, but delirium typically involves more substantial alterations with sleep fragmentation or even complete sleep-wake cycle reversal that reflect disturbed circadian rhythm regulation. The relationship of circadian disturbances to the characteristic fluctuating severity of delirium symptoms over a 24-hour period or to motor disturbance is unknown.

Motor activity alterations are very common in delirium. They have been used to define clinical subtypes (hypoactive, hyperactive, mixed) though studies are inconsistent as to the prevalence of these subtypes. Cognitive impairments and EEG slowing are comparable in hyperactive and hypoactive patients though other symptoms may vary. Psychotic symptoms occur in both although the prevailing stereotype suggests that they only occur in hyperactive cases. Hypoactive cases are prone to non detection or misdiagnosis as depression. A range of studies suggest that motor subtypes differ regarding underlying pathophysiology, treatment needs, and prognosis for function and mortality though inconsistent subtype definitions and poorer detection of hypoactives impacts interpretation of these findings.

Psychotic symptoms occur in up to 50% of patients with delirium. While the common non-medical view of a delirious patient is one who is hallucinating, most people who are medically delirious do not have either hallucinations or delusions. Thought content abnormalities include suspiciousness, overvalued ideation and frank delusions. Delusions are typically poorly formed and less stereotyped than in schizophrenia or Alzheimer’s disease. They usually relate to persecutory themes of impending danger or threat in the immediate environment (e.g. being poisoned by nurses). Misperceptions include depersonalisation, delusional misidentifications, illusions and hallucinations. Hallucinations and illusions are frequently visual though can be tactile and auditory. Abnormalities of affect which may attend the state of delirium may include many distortions to perceived or communicated emotional states. Emotional states may also fluctuate, so that a delirious person may rapidly change between, for example, terror, sadness and jocularity.