Psychopathology: disturbances of thought process – characteristics and clinical conditions
How thinking is disturbed in its form, its possession and its content. The disorders of tempo, flow and connection that make up formal thought disorder, obsessions and compulsions, thought insertion, withdrawal and broadcasting, delusions and overvalued ideas, and Schneider's first-rank symptoms, with the conditions in which each is seen.
- 12 min read
- 5 questions
- Checked 26 Oct 2026
Contents4 sections
At a glance
- Thought is examined through speech and through the patient's account. Its form (how thoughts follow each other), its possession (whether they feel one's own) and its content (what is thought) are disturbed separately; the syllabus's "thought process" is the form, and this page covers form and content.
- Flight of ideas, with pressure of speech, is typical of mania; loosening of associations (derailment, incoherence, neologisms) and thought blocking of schizophrenia; perseveration of organic brain disease; circumstantiality of epilepsy, intellectual disability and obsessional personalities.
- Obsessions are recognised as one's own, felt to be senseless and resisted; thoughts felt to be put in, taken out or broadcast by an outside agency are psychotic, first-rank symptoms.
- A delusion is a false belief held with complete conviction, not changed by evidence and not explained by the person's culture. Primary delusions arise without an understandable cause; secondary ones follow from mood, hallucinations or cognitive impairment.
- Delusions of guilt and nihilism carry a risk of suicide, and delusions of jealousy, persecution and misidentification a risk of violence: the content of a delusion guides the risk assessment.
- An overvalued idea is an understandable belief that dominates a life, as in anorexia nervosa; it is less fixed than a delusion and not resisted like an obsession.
- Schneider's first-rank symptoms (thought echo, voices arguing or commenting, thought insertion, withdrawal and broadcasting, passivity experiences, delusional perception) shaped ICD-10's criteria for schizophrenia, but they also occur in mania and organic psychoses and are absent in many people with schizophrenia.
Thought, and how it is examined
Thinking cannot be observed directly. The doctor infers its form from the patient's speech and asks about its content and about how the patient experiences it. British psychopathology divides it into four areas, and other traditions use three:
| Area | The question | Examples |
|---|---|---|
| Stream (tempo and flow) | how fast, and does it run smoothly? | flight of ideas, retardation, thought blocking |
| Form | are the thoughts connected logically? | loosening of associations, neologisms |
| Possession | do the thoughts feel like one's own and under one's control? | obsessions, thought insertion, withdrawal, broadcasting |
| Content | what is the patient thinking about? | preoccupations, delusions, overvalued ideas, suicidal ideas |
Formal thought disorder, the disorganised speech of DSM, means the disturbances of stream and form together. Speech examples are recorded word for word, because they are the only evidence.
Disturbances of the form of thought
Tempo and flow
| Disturbance | Characteristics | Clinical conditions |
|---|---|---|
| Flight of ideas | thoughts come fast, the topic shifts constantly, and the links are chance associations (sounds, puns, rhymes, things in the room) that can still be followed, while the goal is lost | mania and hypomania, stimulant intoxication |
| Pressure of thought and of speech | the patient feels thoughts racing; speech is rapid, loud, copious and hard to interrupt | mania, stimulants, agitated states |
| Retardation (slowed thinking) | few thoughts, slow and effortful, with long pauses before answers | depression, hypothyroidism, Parkinson's disease and other subcortical disorders, sedative drugs |
| Poverty of thought (alogia) | few thoughts and little speech: brief, empty answers, or adequate speech that conveys little (poverty of content) | negative symptoms of schizophrenia, depression, dementia |
| Thought blocking | a sudden stop in the middle of a thought or sentence, the mind blank, then a new topic | schizophrenia; experienced as thought withdrawal if the patient feels the thought was taken |
| Circumstantiality | many irrelevant details and digressions, but the point is reached in the end | temporal lobe epilepsy, intellectual disability, dementia, obsessional (anankastic) personality, mild mania |
| Tangentiality | answers drift away from the question along related lines and never return to it | schizophrenia, mania, organic states |
| Perseveration | a word, idea or answer repeated after it is no longer appropriate, such as answering the previous question again | organic brain disease, especially frontal; dementia; less often schizophrenia |
| Verbigeration | meaningless repetition of words or syllables | catatonia, organic states |
Connection and coherence
| Disturbance | Characteristics | Clinical conditions |
|---|---|---|
| Loosening of associations (asyndesis) | the general term for a loss of logical connection between ideas, which Bleuler held fundamental to schizophrenia | schizophrenia, mania |
| Derailment (knight's move thinking) | the train of thought slips onto an unrelated track between one clause or sentence and the next | schizophrenia, mania |
| Incoherence, word salad (schizophasia) | connections lost within sentences, with grammar broken, so that only the words are recognisable | severe schizophrenia; the speech of Wernicke's aphasia can sound similar |
| Fusion and muddling | unrelated ideas merged into one, or a jumble of fusion and derailment | schizophrenia |
| Neologisms | new words, or ordinary words given a private meaning; word approximations ("handshoes" for gloves) | schizophrenia; paraphasias in aphasia |
| Clang associations | words chosen for their sound rather than their meaning | mania, schizophrenia |
| Concrete thinking | loss of abstraction: a proverb is explained literally ("people in glass houses shouldn't throw stones, because the glass would break") | schizophrenia, organic brain disease, intellectual disability, autism; depends on culture and education |
| Overinclusion | failure to keep the boundaries of a concept, so that loosely related ideas crowd in | schizophrenia |
| Incoherence of delirium | fragmented, slowed, rambling speech in clouded consciousness, with disorientation | delirium, intoxication |
Point at a name or a part to light it.
Normal thinking moves from a question to its point, each idea leading to the next. In circumstantiality the point is reached by a long way round; in tangentiality it is never reached; flight of ideas races from idea to idea by understandable links, as in mania; derailment slips onto unrelated tracks with no link, in schizophrenia and also in mania; in thought blocking the train stops dead and the mind goes blank.
Simplified: ideas drawn as beads and links as lines; real thinking has no such units; speed is shown only by how close the ideas are; each disorder drawn alone; in a patient they mix and vary from minute to minute.
2 sources
- Semple D, Smyth R. Oxford Handbook of Psychiatry, 4th edition. Oxford University Press, 2019. Chapter 2, Psychiatric assessment (thought disorder); chapter 3, Symptoms of psychiatric illness, pp. 99–120.
- Oyebode F. Sims' Symptoms in the Mind, Textbook of Descriptive Psychopathology, 7th edition. Elsevier, 2022. Disorders of the form of thought (formal thought disorder).
Disturbances of the possession of thought
Obsessions and compulsions
Obsessions are recurrent, persistent thoughts, images or urges that intrude unwanted. The person recognises them as a product of their own mind, finds them senseless, repugnant or excessive, and tries to resist or neutralise them, with rising anxiety. Common themes are contamination, harm and aggression (harming a child or partner), sexual and religious thoughts, doubt (did I lock the door?) and a need for symmetry or order. Obsessional ruminations are repetitive, inconclusive inner debates.
Compulsions are repetitive acts (washing, checking, ordering, touching) or mental acts (counting, praying, repeating phrases) that the person feels driven to perform in response to an obsession or by rigid rules, to reduce anxiety or prevent a feared event. They are not realistically connected to what they prevent, or are clearly excessive, and give no pleasure, which separates them from impulsive acts.
| Obsessions | Compulsions | |
|---|---|---|
| What | thoughts, images, urges | behaviours or mental acts |
| Effect | raise anxiety or disgust | lower it for a time, which reinforces them |
| Attitude | recognised as one's own, resisted | done reluctantly, recognised as excessive |
| Example | "My hands are contaminated" | washing for an hour |
They define obsessive-compulsive disorder (F42 in ICD-10, present on most days for at least 2 weeks and distressing or disabling). They also occur in depression, schizophrenia (sometimes provoked by clozapine), Tourette syndrome, anorexia nervosa and after childbirth. The repetitive, comforting routines of autism and the ego-syntonic perfectionism of anankastic personality disorder are not obsessions, because they are not resisted. People with obsessional thoughts of harm almost never act on them, and saying so clearly is part of treatment.
Thought alienation
In thought alienation the patient experiences his thinking as under the control of an outside agency. These are psychotic experiences and first-rank symptoms:
- Thought insertion: thoughts that are not the patient's own are put into his mind from outside. Not "I have strange thoughts", but "these are someone else's thoughts in my head".
- Thought withdrawal: thoughts are taken out of the mind, which the patient feels as a sudden emptiness, often with thought blocking.
- Thought broadcasting: thoughts leave the mind and are known to others, not because they show on the face but because they spread out of it.
- Thought echo is related but is a hallucination: hearing one's own thoughts spoken aloud.
The patient often adds an explanation (a transmitter, a chip, the secret service), but it is the experience itself that counts.
Disturbances of the content of thought
Delusions
A delusion is a belief held with complete subjective certainty, not changed by evidence or argument to the contrary, and not explained by the person's culture, religion or education. Jaspers named three marks: certainty, incorrigibility and falsity of content. The content is usually false, but not always: in delusional jealousy the partner may be unfaithful, and what makes the belief delusional is how it was reached and how it is held.
Delusions are described by their conviction, how much they preoccupy the patient, how far they are systematised into a coherent scheme, whether they fit the mood (mood-congruent or incongruent), whether they are bizarre (impossible in the patient's culture), and whether the patient acts on them.
| Kind | How it arises | Examples |
|---|---|---|
| Primary | not understandable from other experiences; arises directly from the illness | delusional mood (a sense that something strange and threatening is going on, with perplexity, until a delusion crystallises), delusional perception (a normal perception suddenly given a delusional meaning), autochthonous delusion (a belief that arrives fully formed out of the blue), delusional memory (a memory given a new delusional meaning) |
| Secondary | understandable from mood, hallucinations, other delusions, cognitive impairment or isolation | guilt in severe depression, grandiosity in mania, persecution explaining voices, theft explaining lost belongings in dementia |
Primary delusions point to schizophrenia; secondary delusions occur in any psychosis.
| Type | Content | Clinical conditions |
|---|---|---|
| Persecutory | being watched, followed, poisoned, harmed or conspired against; the commonest type | schizophrenia, delusional disorder, mania, psychotic depression (with the sense of deserving it), delirium, dementia, stimulant psychosis |
| Reference | events, remarks, broadcasts or number plates carry a special message for the patient | schizophrenia, delusional disorder; ideas of reference, held with insight, in sensitive and socially anxious people |
| Grandiose | special powers, wealth, identity, talent or mission | mania, schizophrenia, delusional disorder |
| Nihilistic | organs rotting or stopped, the body or the world no longer exists, the patient is dead (Cotard syndrome) | severe psychotic depression, especially in older people; schizophrenia; organic states |
| Guilt and worthlessness | having committed terrible sins or crimes, causing disasters, deserving punishment | psychotic depression |
| Poverty | ruin, the family will starve | psychotic depression in older people |
| Somatic and hypochondriacal | having cancer or another fatal illness, being infested by parasites (delusional infestation), emitting a smell, being deformed | psychotic depression, delusional disorder (somatic type), schizophrenia; infestation also in cocaine use and dementia |
| Jealousy (Othello syndrome) | the partner is unfaithful, "proved" by trivial signs; checking, interrogation, following | alcohol dependence, delusional disorder, schizophrenia, organic brain disease; more often in men |
| Erotomanic (de Clérambault syndrome) | a person, usually of higher status and often hardly known, is in love with the patient | delusional disorder, schizophrenia, mania; can lead to stalking |
| Control (passivity) | feelings, impulses, actions or bodily sensations are made or controlled by an outside force | schizophrenia, a first-rank symptom |
| Misidentification | a familiar person has been replaced by an identical impostor (Capgras), or strangers are a known persecutor in disguise (Fregoli) | schizophrenia, dementia with Lewy bodies and Alzheimer's disease, right hemisphere lesions |
| Religious | a special relationship with God, a divine mission, possession by the devil | schizophrenia, mania; told apart from beliefs shared within the patient's faith |
A delusion can be shared: in induced delusional disorder (folie à deux, F24) a dependent partner takes on the delusion of the ill one and usually loses it on separation. A delusion that stands alone, without other psychotic symptoms, for at least 3 months, is a persistent delusional disorder (F22; see other psychotic disorders).
Overvalued ideas
An overvalued idea (Wernicke's term) is a belief that is understandable, often shared to some degree by others, and held with intense feeling, that comes to dominate a person's life and actions. It is less fixed than a delusion and, unlike an obsession, is felt to be justified, not senseless.
| Obsession | Overvalued idea | Delusion | |
|---|---|---|---|
| Felt to be | one's own, senseless or excessive | one's own, justified | one's own and true (unless inserted) |
| Resisted | yes | no, acted on | no |
| Conviction | doubt, fear that it might be true | strong, not absolute | absolute, incorrigible |
| In relation to culture | ordinary content | often a culturally shared value, exaggerated | not explained by culture |
| Typical in | OCD | anorexia nervosa, body dysmorphic disorder, hypochondriasis, paranoid and querulous personalities | the psychoses |
The line between them is not sharp: DSM-5-TR records the insight of OCD and body dysmorphic disorder as good or fair, poor, or absent, and ICD-11 as fair to good or poor to absent, so that a delusional conviction about the body is coded within these disorders rather than as a separate psychosis.
Schneider's first-rank symptoms
Kurt Schneider listed the experiences that, in the absence of organic disease, he thought most suggestive of schizophrenia.
| Group | Symptoms |
|---|---|
| Auditory hallucinations | thought echo (hearing one's thoughts aloud); voices arguing or discussing the patient in the third person; voices giving a running commentary on the patient's actions |
| Thought alienation | thought insertion, thought withdrawal, thought broadcasting |
| Passivity experiences | made feelings, made impulses, made actions (volition), and somatic passivity, bodily sensations imposed from outside |
| Delusional perception | a normal perception given a sudden delusional meaning |
ICD-10 builds its criteria for schizophrenia on them: at least one very clear symptom from thought echo, insertion, withdrawal or broadcasting, passivity and delusional perception, commenting or discussing voices, or persistent culturally impossible delusions, or at least two of persistent hallucinations with delusions, formal thought disorder, catatonia and negative symptoms, for most of the time for at least a month.
They are less specific than Schneider thought. A Cochrane review found them in fewer than six in ten people with schizophrenia, and in about one in five people with other diagnoses, and they occur in mania and in organic psychoses. DSM-5 gives them no special weight; ICD-11 keeps experiences of influence, passivity and control among its core symptoms. They are easy to ask about and remain a useful clinical sign, but their absence does not exclude schizophrenia, and their presence does not prove it.
Check yourselfAnswer, then say how sure you were: a lucky guess still counts as a weak point.
1Asked how she has been sleeping, a 30-year-old woman answers rapidly and cannot be interrupted, "Like a log, logs burn, burn your bridges, bridges in Paris, I must fly to Paris tonight, Paris is for lovers and I love everyone." What is this?
2Three weeks after giving birth, a 29-year-old woman has repeated images of stabbing her baby. She finds them horrifying, knows they come from her own mind, tries to push them away and has hidden the kitchen knives. She has no other psychotic symptoms. What are these?
3A 21-year-old man sees a red car parked outside his flat and at that moment knows, with complete certainty, that he has been chosen to lead a revolution. He cannot explain how he knows. What is this?
4A 52-year-old man who drinks heavily is convinced that his wife is unfaithful. He checks her phone, follows her to work and examines the sheets for stains, and nothing she says shakes his belief. What is the most important concern?
5A 17-year-old girl with a body mass index of 15 believes she is too fat and must lose more weight. The belief dominates her day and she defends it with reasons, but it is not bizarre and many young women share a version of it. How is this belief best described?