4 Classification and assessment in psychiatry4.1 Descriptive psychopathology
4.1.5 Disorders of speech and thought
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Written by Resident Doctor Committee · Published
Speech, language and thought
Thought cannot be observed directly. Its form is inferred from what the person says.
Level | What it is | How it is assessed |
|---|---|---|
Speech | The physical utterance, observed directly | Rate, volume, rhythm, articulation, prosody |
Language | The system that carries meaning | Naming, comprehension, repetition, reading, writing |
Thought form | The organisation of what is said, inferred | Coherence and goal-direction of spontaneous speech |
Phonology is the component of language concerned with the sound system and its phonemes.
Syntax and semantics are further components of language, and semantics is literal meaning.
Pragmatics governs how language is used in social context: what a speaker means in a given setting, as opposed to what the words literally mean.
Fluent receptive aphasia can look like thought disorder. Naming, comprehension and repetition stay intact in formal thought disorder and fail in the aphasias, so test all three and look for neurological signs.
Four domains of thought
Domain | What it covers | Examples |
|---|---|---|
Stream | Tempo and continuity | Flight of ideas, retarded thinking, thought block |
Form | How ideas link | Derailment, circumstantiality, word salad |
Content | What is believed | All delusions, overvalued ideas |
Possession | Ownership and control of thought | Obsessions, thought alienation |
Formal thought disorder is a disturbance of form, distinct from disorders of content, possession and motor speech.
Dereistic thinking is thought turned away from reality, driven by wish and fantasy and following a private logic.
Stream of thought
Speeding up
Flight of ideas is a rapid run of thoughts whose goal keeps shifting while each link to the next stays traceable, often through rhyme, pun or a stock phrase; it is typical of mania.
In derailment, by contrast, the links cannot be followed.
Clang association links successive words by sound, as in rhyming, in the rapid speech of mania; punning links them by a word's double meaning.
Accelerated thinking is subjective racing with objective speeding, seen in mania and with stimulants.
Pressure of thought is the patient's subjective report of accelerated, racing ideas, and it can coexist with objectively normal speech.
Crowded thoughts are an unpleasant overfilling of the mind that cannot be halted and belong chiefly to depressed mood; the racing thoughts of mania are fast and pleasant.
In schizophrenia, crowding of thought is reported as too many compressed thoughts at once; it is a subjective report, whereas flight of ideas is observed in speech.
Slowing down
Slowed thinking in depressive illness is a disturbance of the stream of thought.
Inhibited thinking is the subjective form, which the patient reports; retarded thinking is the objective form, which the examiner observes in speech.
Increased latency is a long pause before each reply, seen in depression and schizophrenia.
Poverty of thought is having few thoughts, experienced as emptiness, in depression and negative-symptom schizophrenia.
Interruption
Thought block is a sudden, complete interruption of the train of thought, with a blank mind and no attribution to an outside agency; it is classically seen in schizophrenia.
Thought withdrawal adds the belief that an outside agency has removed the thoughts.
Disruption of thought is the subjective experience of thoughts breaking off that corresponds to objectively observed thought blocking, with no pause seen in speech and no belief in outside interference.
Derailment runs on without a gap, whereas thought block leaves one.
Form of thought
Losing the goal
Abnormality | What happens | Reaches the goal? |
|---|---|---|
Circumstantiality | Indirect, slow speech overloaded with detail | Yes, eventually |
Tangentiality | Organised speech answers a question obliquely from the outset, then drifts away | No |
Derailment (loosening of associations, knight's move thinking) | Spontaneous speech slides to an unrelated or obliquely related idea, often through a traceable link and without a pause | No |
Loss of goal | A long reply that never arrives anywhere | No |
Circumstantiality is a disorder of thought form seen in several psychiatric and neurological conditions, but not in the aphasias, which disturb language rather than the organisation of thought.
Circumstantiality is classically linked with obsessive-compulsive (anankastic) personality disorder, not with obsessive-compulsive disorder (OCD).
Illogicality is reaching conclusions that do not follow from the premises.
Distractibility is speech diverted by whatever is happening nearby.
Tangentiality begins as an oblique reply to a question; derailment arises within spontaneous speech.
Classical descriptions
Carl Schneider described five features of schizophrenic formal thought disorder: derailment, substitution, omission, fusion and drivelling.
Substitution is a major thought replaced by a subsidiary one.
Fusion (Verschmelzung) is the interweaving of two unrelated trains of thought into one.
Cameron's asyndesis and overinclusion are not among Schneider's five.
Author | Term | Meaning |
|---|---|---|
Cameron | Asyndesis | No adequate causal or meaningful links between successive thoughts, though each statement makes sense alone; often described as loosening of associations |
Cameron | Overinclusion | Failure to hold the boundaries of a concept, so a category stretches to take in loosely related things |
Goldstein | Concrete thinking | Loss of the abstract attitude, so thinking stays literal |
Interpret proverb testing for concrete thinking against the person's education, language and culture.
Incoherence and odd words
Word salad (incoherence, schizophasia) is the most extreme formal thought disorder, with no understandable link even between neighbouring words and with collapsed grammar.
A neologism is a newly coined word, not in the language, carrying a private meaning for the speaker within otherwise grammatical speech.
Metonymy is using a related but non-standard existing word or phrase in place of the proper one, seen in schizophrenic thought disorder.
Parapraxis is a faulty act in a healthy person, such as a slip of the tongue or pen, which Freud attributed to unconscious motives.
A neologism is a word-level phenomenon, whereas word salad is a failure at the level of the sentence.
Formal thought disorder in research
Poverty of content of speech is a normal amount of speech that conveys little because it is vague, over-abstract or empty.
Andreasen found poverty of content of speech more often in schizophrenia than in mania, while most positive thought, language and communication items are common to both.
The form of thought disorder at the height of an acute schizophrenic episode has no established value for predicting relapse.
The type-token ratio measures lexical diversity, the number of distinct words against all words spoken, and is reported lower in schizophrenia.
Semantic priming spreads through a network of concepts.
Indirect (mediated) priming, where prime and target are linked only through a third concept, is reported as enlarged in formal thought disorder.
Amount and rate of speech
Finding | Description |
|---|---|
Logorrhoea | Excess in the amount of speech with form intact: logical, at a normal pace and interruptible |
Rapid speech | Fast, but the patient yields when the interviewer speaks |
Pressured speech | Rapid, excessive, driven and hard to interrupt; recorded as a speech abnormality, separately from thought form |
Alogia (poverty of speech) | Reduced output and elaboration, but speech is still attempted |
Mutism | Complete absence of speech with preserved comprehension, clear consciousness and an intact speech apparatus |
Selective mutism | Muteness confined to particular settings, such as school, in a child who speaks normally elsewhere |
Repetition and other speech abnormalities
Phenomenon | What is repeated | Where it is seen |
|---|---|---|
Echolalia | Words or phrases just spoken by another person, automatically; the verbal counterpart of echopraxia | Catatonia, autism, frontal lobe disease, learning disability, some dementias |
Palilalia | A whole word the speaker has just said, involuntarily, often speeding up and fading | Parkinsonism, other basal ganglia and frontal disorders |
Logoclonia | Only the final syllable of a word | Described by Kraepelin in advanced early-onset Alzheimer's disease; late dementia; logopenic variant of primary progressive aphasia |
Verbigeration | The patient's own meaningless words or phrases, in stereotyped form | Catatonia, chronic schizophrenia |
Perseveration | A response that fitted an earlier stimulus, after the stimulus has changed | Organic disease: frontal lobe damage, dementia, delirium |
Perseveration points to organic disease but does not localise it to one site.
Stereotypy repeats a fixed utterance from the outset, whereas perseveration is a response that was once appropriate and has outstayed its stimulus.
Vorbeireden (approximate answers, talking past the point) is the defining feature of Ganser syndrome, which the International Classification of Diseases, 11th revision (ICD-11) places under other specified dissociative disorders.
Witzelsucht is compulsive punning and facetious joking after frontal lobe damage, especially right-sided and orbitofrontal, and it reflects disinhibition.
Prosody and register
Prosody is the intonation, stress and emotional colouring of speech; loss of melodic contour is an abnormality of prosody even when articulation, fluency, rate and amount are intact.
Abnormal prosody is the mental state examination term for atypical, sing-song or robotic speech melody, as in autism spectrum disorder.
Aprosodia is loss of the emotional intonation of speech, in both production and comprehension, after right hemisphere damage, with language and articulation preserved.
Aprosodia is also seen in parkinsonism and with antipsychotics.
Stilted speech is excessively formal, pompous or old-fashioned for the social setting, with correct vocabulary, and is seen in the social communication difficulty of autism spectrum disorder.
In abnormal prosody the voice varies too much and in the wrong places; in monotony it barely varies at all.
Voice and articulation
Dysphonia is an altered quality or volume of the voice, whereas aphonia is complete loss of voice with only a whisper left.
Hoarseness after thyroid surgery suggests injury to the recurrent laryngeal branch of the vagus nerve.
A whispered voice with a normal cough, sudden onset after distress and inconsistent findings indicates a dissociative neurological symptom disorder with speech disturbance, which ICD-11 recognises.
A stammer is a pattern of repetitions, prolongations and blocks, usually developmental.
Dysarthria is a motor disorder of articulation in which language is intact on every test: comprehension, naming, repetition, reading and writing.
Dysarthria | How it sounds | Cause | Examples |
|---|---|---|---|
Hypokinetic | Soft and flat, in short rushes | Rigidity and poverty of movement | Parkinson's disease |
Hyperkinetic | Involuntary movements break into speech | Involuntary movement disorders | Tardive dyskinesia, chorea of Huntington's disease |
Ataxic (scanning) | Separated syllables, equal or irregular stress, explosive delivery | Cerebellum | Friedreich's ataxia, lithium toxicity |
Flaccid | Nasal and indistinct | Lower motor neurone or neuromuscular junction weakness | Bulbar palsy with a wasted, limp tongue; myasthenia gravis, where speech worsens with use and recovers with rest |
Spastic | Slow, effortful and high-pitched, with a stiff tongue and brisk jaw jerk | Bilateral upper motor neurone (corticobulbar) damage | Pseudobulbar palsy |
Aphasia
Type | Output | Comprehension | Repetition |
|---|---|---|---|
Broca's (expressive) | Non-fluent, effortful, often agrammatic | Largely preserved | Impaired |
Wernicke's (receptive) | Fluent but often empty or paraphasic | Impaired | Impaired |
Transcortical motor aphasia is as non-fluent as Broca's aphasia but repeats well.
Semantic paraphasia replaces the intended word with a real word related in meaning, as after a dominant-hemisphere stroke.
Phonemic paraphasia substitutes a word by its sound.
New language impairment, especially of sudden onset, needs urgent neurological assessment.
Telling beliefs and intrusions apart
Phenomenon | Conviction or appraisal | Resisted? | Felt as |
|---|---|---|---|
Obsession | Recognised as senseless or excessive | Yes, at the cost of rising anxiety | Ego-dystonic, own thought |
Depressive rumination | Accepted as reasonable thinking, mood-congruent | No | Own thinking |
Overvalued idea | Strong, but less than delusional | No | Own, not senseless |
Delusion | Full, fixed conviction | No | Ego-syntonic |
Depersonalisation, derealisation | Recognised as strange | Yes, unwelcome | Ego-dystonic |
Catastrophic misinterpretation is the in-the-moment reading of a harmless bodily sensation as a sign of imminent disaster, and in Clark's cognitive model it drives panic.
Obsessions and compulsions
Obsessions
An obsession is a recurrent, intrusive, unwanted thought, image or impulse that the person recognises as their own, finds senseless or excessive and resists; insight is retained.
Obsessions are not only verbal thoughts: they also occur as mental images and as impulses or urges.
Obsessions recur in a stereotyped form, essentially unchanged in content each time they enter the mind.
Recognising the thought as one's own separates an obsession from thought insertion, which is attributed to an outside source.
Intrusive harm, sexual or blasphemous thoughts do not equal intent, but actual risk is still assessed.
Compulsions
A compulsion is a driven, rule-bound, anxiety-reducing repetitive act that the person resists and sees as senseless, defined by its neutralising function.
A compulsion can be an overt, repeated motor act or a purely mental (covert) one.
A compulsion need not follow an obsessional thought: it may follow an image, impulse or word, or occur with no preceding obsession.
Brief relief after the act reinforces repetition.
Obsessional slowness in OCD arises mainly from obsessions of symmetry, ordering and exactness.
Act | What drives it | How it feels |
|---|---|---|
Compulsion | Deliberate and rule-bound, to ease anxiety or reach a just-right sense of completion | Resisted, senseless |
Habit | Automatic | Comfortable |
Tic | Discharges a premonitory bodily urge | A single brief movement when simple, a coordinated sequence when complex |
An obsession arises in the mind; a compulsion is something done, a behaviour or a mental act, to reduce anxiety.
Overvalued ideas
An overvalued idea is an understandable, emotionally charged, unreasonable belief, often grounded in real experience, that dominates thinking and behaviour.
Overvalued ideas are a core feature of several disorders, including eating, body image and health-related presentations, but not of depersonalisation-derealisation disorder, whose defining feature is an altered experience with insight intact.
Dysmorphophobia, an overvalued preoccupation with an imagined or slight flaw in appearance, is most typically a feature of body dysmorphic disorder.
Delusions
What counts as a delusion
A delusion is a belief held with marked conviction despite contrary evidence and not adequately explained by cultural context.
Whether a belief is factually true or false does not by itself decide whether it is delusional.
A belief that is plausible, matches the facts and is held without fixed conviction, yielding to reassurance, is not a delusion, even in a depressed person.
A delusion of reference is a fixed belief, held with full conviction, that neutral events, gestures, comments or media carry a special message aimed at oneself.
An idea of reference is the same sense of being talked about, while accepting that it may be imagined.
Primary and secondary delusions
Jaspers distinguished two kinds by whether the belief can be understood from what came before it.
A primary delusion is psychologically irreducible, with no comprehensible antecedent in mood, perception or experience.
"Primary" is a descriptive term: it does not mean the belief has no cause.
A secondary delusion is understandable from a preceding hallucination, mood state, cognitive deficit or earlier delusion, though it does not always resolve as soon as these improve.
A primary delusion, once formed, can be elaborated into a systematised structure, and an autochthonous delusion can be the nucleus around which secondary delusions are built.
Primary delusions are classed by how the belief first arises. Misidentification is not one of the classes.
Type | How it arises |
|---|---|
Delusional mood (Wahnstimmung) | A perplexed, apprehensive prodromal state in which the world feels charged with significance before any specific delusion forms; relief often follows when the delusion crystallises |
Delusional perception | An accurate, ordinary perception is followed at once by an unshakeable, unrelated delusional meaning, with no preceding mood change or hallucination |
Delusional memory | A real memory is given a new, fixed delusional significance, or a false memory carries delusional content, without mood change or hallucination |
Autochthonous delusion | The belief arises fully formed, with no antecedent in mood, perception or experience |
Delusional perception is the only primary delusional experience on Schneider's first-rank list; delusional mood is primary but not first-rank.
The Wahneinfall is the sudden, formed delusional idea, as distinct from the mood that precedes it.
Carl Wernicke first described autochthonous ideas, which appear abruptly in awareness with no source in preceding thought or perception.
Conrad's stages of delusional psychosis
Conrad's staged model of delusional psychosis runs in five stages: trema (delusional mood), apophany (searching for and finding personal meaning), anastrophy, consolidation and residuum.
Structure and course
Term | Meaning |
|---|---|
Systematised delusion | A set of false beliefs logically linked and organised around one theme |
Autistic delusion | The patient lives wholly inside the delusional world, with no regard for external reality |
Polarised delusion | Real events are woven into the delusion and each shapes the other |
Juxtaposed delusion | The delusion runs side by side with real experience without interacting |
The underlying diagnosis, specifically schizophrenia, predicts persistence of delusions more strongly than demographics or delusional content.
Themes
Theme | Content |
|---|---|
Persecutory | Being watched, followed, poisoned or conspired against |
Grandiose | Exceptional identity, ability, wealth or mission; mood-congruent in mania |
Guilt, poverty and nihilism | Unforgivable acts, ruin, or the non-existence of self, organs or world; secondary to depression |
Religious | Divine identity or mission beyond cultural norms |
Jealousy | A partner's infidelity |
Erotomanic | Another person, often inaccessible or of higher status, is in love with oneself |
Control and passivity | Thoughts, feelings or acts produced from outside |
Capgras delusion is the belief that a person who looks exactly like a spouse is an impostor who has replaced them; it is seen in schizophrenia and often in dementia with Lewy bodies.
Fregoli delusion is the belief that one known person, often a persecutor, is disguised as several strangers.
Intermetamorphosis is the belief that other people change physically into the familiar person.
Clinical lycanthropy is the delusional belief that one has been transformed into an animal.
Thought possession
Thought alienation (insertion, withdrawal and broadcasting) concerns the ownership, control and privacy of thought.
Schneider's thought alienation experiences are first-rank positive symptoms.
Negative symptoms of schizophrenia are losses of normal function: alogia, avolition, anhedonia, asociality and blunted affect.
Gedankenlautwerden (audible thoughts, thought echo, écho de la pensée) is hearing one's own thoughts spoken aloud as, or just after, they are thought; it is a Schneiderian first-rank symptom.
In thought broadcasting, the person believes others know their thoughts, but nothing is heard.
Clarify the actual experience rather than inferring broadcasting from a phrase such as "people know my thoughts".