A thought disorder (TD) is a disturbance in
cognition
Cognition is the "mental action or process of acquiring knowledge and understanding through thought, experience, and the senses". It encompasses all aspects of intellectual functions and processes such as: perception, attention, thought, ...
which affects
language
Language is a structured system of communication that consists of grammar and vocabulary. It is the primary means by which humans convey meaning, both in spoken and signed language, signed forms, and may also be conveyed through writing syste ...
, thought and
communication
Communication is commonly defined as the transmission of information. Its precise definition is disputed and there are disagreements about whether Intention, unintentional or failed transmissions are included and whether communication not onl ...
.
Psychiatric and psychological glossaries in 2015 and 2017 identified thought disorders as encompassing
poverty of ideas, paralogia (a reasoning disorder characterized by expression of illogical or delusional thoughts),
word salad
A word salad is a "confused or unintelligible mixture of seemingly random words and phrases", most often used to describe a symptom of a neurological or mental disorder. The name schizophasia is used in particular to describe the confused langua ...
, and
delusion
A delusion is a fixed belief that is not amenable to change in light of conflicting evidence. As a pathology, it is distinct from a belief based on false or incomplete information, confabulation, dogma, illusion, hallucination, or some other m ...
s—all disturbances of thought content and form. Two specific terms have been suggested—content thought disorder (CTD) and formal thought disorder (FTD). CTD has been defined as a thought disturbance characterized by multiple fragmented delusions, and the term ''thought disorder'' is often used to refer to an FTD: a disruption of the form (or structure) of thought.
Also known as disorganized thinking, FTD results in disorganized speech and is recognized as a major feature of
schizophrenia
Schizophrenia () is a mental disorder characterized variously by hallucinations (typically, Auditory hallucination#Schizophrenia, hearing voices), delusions, thought disorder, disorganized thinking and behavior, and Reduced affect display, f ...
and other
psychoses
In psychopathology, psychosis is a condition in which a person is unable to distinguish, in their experience of life, between what is and is not real. Examples of psychotic symptoms are delusions, hallucinations, and disorganized or incoher ...
(including
mood disorder
A mood disorder, also known as an affective disorder, is any of a group of conditions of mental and behavioral disorder where the main underlying characteristic is a disturbance in the person's mood. The classification is in the ''Diagnostic ...
s,
dementia
Dementia is a syndrome associated with many neurodegenerative diseases, characterized by a general decline in cognitive abilities that affects a person's ability to perform activities of daily living, everyday activities. This typically invo ...
,
mania
Mania, also known as manic syndrome, is a Psychiatry, psychiatric Abnormality (behavior), behavioral syndrome defined as a state of Abnormality (behavior), abnormally elevated arousal, affect (psychology), affect, and energy level. During a mani ...
, and
neurological diseases
Neurological disorders represent a complex array of medical conditions that fundamentally disrupt the functioning of the nervous system. These disorders affect the brain, spinal cord, and nerve networks, presenting unique diagnosis, treatment, and ...
).
Disorganized speech leads to an inference of disorganized thought. Thought disorders include
derailment
In rail transport, a derailment is a type of train wreck that occurs when a rail vehicle such as a train comes off its rails. Although many derailments are minor, all result in temporary disruption of the proper operation of the railway sys ...
,
pressured speech
Pressure of speech (or pressured speech) is a speech fast and frenetic (i.e., mainly without pauses), including some irregularities in loudness and rhythm or some degrees of circumstantiality; it is hard to interpret and expresses a feeling/ affect ...
,
poverty of speech,
tangentiality
Tangential speech or tangentiality is a communication disorder in which the train of thought of the speaker wanders and shows a lack of focus, never returning to the initial topic of the conversation.''Forensic Aspects of Communication Sciences and ...
,
verbigeration, and
thought blocking.
One of the first known public presentations of thought disorders, or specifically OCD as it is known today, was in 1691. Bishop John Moore gave a speech before Queen Mary II, about "religious melancholy."
Formal thought disorder affects the form (rather than the content) of thought.
Unlike hallucinations and delusions, it is an observable, objective sign of psychosis.
FTD is a common core symptom of a psychotic disorder, and may be seen as a marker of severity and as an indicator of prognosis.
It reflects a cluster of cognitive, linguistic, and affective disturbances that have generated research interest in the fields of cognitive neuroscience, neurolinguistics, and psychiatry.
Eugen Bleuler
Paul Eugen Bleuler ( ; ; 30 April 1857 – 15 July 1939) was a Swiss psychiatrist and eugenicist most notable for his influence on modern concepts of mental illness. He coined several psychiatric terms including "schizophrenia", " schizoid", "a ...
, who named
schizophrenia
Schizophrenia () is a mental disorder characterized variously by hallucinations (typically, Auditory hallucination#Schizophrenia, hearing voices), delusions, thought disorder, disorganized thinking and behavior, and Reduced affect display, f ...
, said that TD was its defining characteristic.
[Colman, A. M. (2001) ''Oxford Dictionary of Psychology'', Oxford University Press. ] Disturbances of thinking and speech, such as
clanging
Clanging (or clang associations) is a symptom of mental disorders, primarily found in patients with schizophrenia and bipolar disorder. This symptom is also referred to as association chaining, and sometimes, glossomania.
Steuber defines it as "re ...
or
echolalia
Echolalia is the unsolicited repetition of vocalizations made by another person; when repeated by the same person, it is called palilalia. In its profound form it is automatic and effortless. It is one of the echophenomena, closely related to ...
, may also be present in
Tourette syndrome
Tourette syndrome (TS), or simply Tourette's, is a common neurodevelopmental disorder that begins in childhood or adolescence. It is characterized by multiple movement (motor) tics and at least one vocal (phonic) tic. Common tics are blinkin ...
;
other symptoms may be found in
delirium
Delirium (formerly acute confusional state, an ambiguous term that is now discouraged) is a specific state of acute confusion attributable to the direct physiological consequence of a medical condition, effects of a psychoactive substance, or ...
.
A clinical difference exists between these two groups. Patients with psychoses are less likely to show awareness or concern about disordered thinking, and those with other disorders are aware and concerned about not being able to think clearly.
Content thought disorder
Thought content is the subject of an individual's thoughts, or the types of ideas expressed by the individual.
Mental health professionals define normal thought content as the absence of significant abnormalities, distortions, or harmful thoughts.
Normal thought content aligns with reality, is appropriate to the situation, and does not cause significant distress or impair functioning.
A person's cultural background must be considered when assessing thought content. Abnormalities in thought content differ across cultures. Specific types of abnormal thought content can be features of different psychiatric illnesses.
Examples of disordered thought content include:
* Suicidal thinking: thoughts of ending one's own life.
* Homicidal thinking: thoughts of ending the life of another.
*
Delusion
A delusion is a fixed belief that is not amenable to change in light of conflicting evidence. As a pathology, it is distinct from a belief based on false or incomplete information, confabulation, dogma, illusion, hallucination, or some other m ...
: A fixed, false belief that a person holds despite contrary evidence and that is not a shared cultural belief.
* Paranoid ideation: thoughts, not severe enough to be considered delusions, involving excessive suspicion or the belief that one is being harassed, persecuted, or unfairly treated.
* Preoccupation: excessive and/or distressing thoughts that are stressor-related and associated with negative emotions.
* Obsession: a repetitive thought that is
intrusive or inappropriate and distressing or upsetting.
*
Compulsion
Compulsion, Compulsive, Compelling, or Compulsory may refer to:
Psychology
* Compulsive behavior, a psychological condition in which a person does a behavior compulsively, having an overwhelming feeling that they must do so.
* Obsessive–compul ...
: A repeated behavior or mental act done in response to an obsession. It aims to reduce anxiety or distress. But, it is not feasibly related to the anxiety-provoking stimulus. It is excessive and distressing.
*
Magical thinking
Magical thinking, or superstitious thinking, is the belief that unrelated events are causally connected despite the absence of any plausible causal link between them, particularly as a result of supernatural effects. Examples include the idea tha ...
: A false belief in a causal link between actions and events. The mistaken belief that one's thoughts, words, or actions can cause or prevent an outcome in a way that violates the laws of cause and effect.
* Overvalued ideas: false or exaggerated belief held with conviction, but without delusional intensity.
*
Phobias
The English language, English suffixes -phobia, -phobic, -phobe (from Ancient Greek, Greek φόβος ''phobos'', "fear") occur in technical usage in psychiatry to construct words that describe irrational, abnormal, unwarranted, persistent, o ...
: irrational fears of objects or circumstances that are persistent.
* Poverty of thought: abnormally few thoughts and ideas expressed.
* Overabundance of thought: abnormally many thoughts and ideas expressed.
Formal thought disorder
Thought process is a person's form, flow, and coherence of thinking.
This is how they use language and put ideas together. A normal thought process is logical, linear, meaningful, and goal-directed.
A logical, linear thought process is one that demonstrates rational connections between thoughts in a way that is sequential that allows others to understand.
Thought process is not what a person thinks, rather it is how a person expresses their thoughts.
Formal thought disorder (FTD), also known as disorganized speech or disorganized thinking, is a disorder of a person's thought process in which they are unable to express their thoughts in a logical and linear fashion. To be considered FTD, disorganized thinking must be severe enough that it impairs effective communication.
Disorganized speech is a core symptom of
psychosis
In psychopathology, psychosis is a condition in which a person is unable to distinguish, in their experience of life, between what is and is not real. Examples of psychotic symptoms are delusions, hallucinations, and disorganized or inco ...
, and therefore can be a feature of any condition that has a potential to cause psychosis, including
schizophrenia
Schizophrenia () is a mental disorder characterized variously by hallucinations (typically, Auditory hallucination#Schizophrenia, hearing voices), delusions, thought disorder, disorganized thinking and behavior, and Reduced affect display, f ...
,
mania
Mania, also known as manic syndrome, is a Psychiatry, psychiatric Abnormality (behavior), behavioral syndrome defined as a state of Abnormality (behavior), abnormally elevated arousal, affect (psychology), affect, and energy level. During a mani ...
,
major depressive disorder
Major depressive disorder (MDD), also known as clinical depression, is a mental disorder characterized by at least two weeks of pervasive depression (mood), low mood, low self-esteem, and anhedonia, loss of interest or pleasure in normally ...
,
delirium
Delirium (formerly acute confusional state, an ambiguous term that is now discouraged) is a specific state of acute confusion attributable to the direct physiological consequence of a medical condition, effects of a psychoactive substance, or ...
,
postpartum psychosis
Postpartum psychosis (PPP), also known as puerperal psychosis or peripartum psychosis, involves the abrupt onset of psychotic symptoms shortly following childbirth, typically within two weeks of delivery but less than 4 weeks postpartum. PPP is ...
, major neurocognitive disorder, and
substance induced psychosis.
FTD reflects a cluster of cognitive, linguistic, and affective disturbances, and has generated research interest from the fields of
cognitive neuroscience
Cognitive neuroscience is the scientific field that is concerned with the study of the Biology, biological processes and aspects that underlie cognition, with a specific focus on the neural connections in the brain which are involved in mental ...
,
neurolinguistics
Neurolinguistics is the study of Nervous system, neural mechanisms in the human brain that control the comprehension, production, and acquisition of language. As an interdisciplinary field, neurolinguistics draws methods and theories from fie ...
, and
psychiatry
Psychiatry is the medical specialty devoted to the diagnosis, treatment, and prevention of deleterious mental disorder, mental conditions. These include matters related to cognition, perceptions, Mood (psychology), mood, emotion, and behavior.
...
.
It can be subdivided into clusters of positive and negative symptoms and objective (rather than subjective) symptoms.
On
the scale of positive and negative symptoms, they have been grouped into
positive formal thought disorder (posFTD) and
negative formal thought disorder (negFTD).
Positive subtypes were
pressure of speech,
tangentiality
Tangential speech or tangentiality is a communication disorder in which the train of thought of the speaker wanders and shows a lack of focus, never returning to the initial topic of the conversation.''Forensic Aspects of Communication Sciences and ...
,
derailment
In rail transport, a derailment is a type of train wreck that occurs when a rail vehicle such as a train comes off its rails. Although many derailments are minor, all result in temporary disruption of the proper operation of the railway sys ...
, incoherence, and
illogicality;
negative subtypes were
poverty of speech and poverty of content.
The two groups were posited to be at either end of a spectrum of normal speech, but later studies showed them to be poorly correlated.
A comprehensive measure of FTD is the Thought and Language Disorder (TALD) Scale.
The Kiddie Formal Thought Disorder Rating Scale (K-FTDS) can be used to assess the presence of formal thought disorder in children and their childhood. Although it is very extensive and time-consuming, its results are in great detail and reliable.
Nancy Andreasen preferred to identify TDs as ''thought-language-communication disorders'' (TLC disorders).
Up to seven domains of FTD have been described on the Thought, Language, Communication (TLC) Scale, with most of the variance accounted for by two or three domains.
Some TLC disorders are more suggestive of severe disorder, and are listed with the first 11 items.
Diagnoses
The
DSM-5
The ''Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition'' (DSM-5), is the 2013 update to the '' Diagnostic and Statistical Manual of Mental Disorders'', the taxonomic and diagnostic tool published by the American Psychiat ...
categorizes FTD as "a psychotic symptom, manifested as bizarre speech and communication." FTD may include incoherence, peculiar words, disconnected ideas, or a lack of unprompted content expected from normal speech.
Clinical psychologists
Clinical psychology is an integration of human science, behavioral science, theory, and clinical knowledge for the purpose of understanding, preventing, and relieving psychologically-based distress or Mental disorder, dysfunction and to promote ...
typically assess FTD by initiating an exploratory conversation with patients and observing the patient's verbal responses.
FTD is often used to establish a diagnosis of
schizophrenia
Schizophrenia () is a mental disorder characterized variously by hallucinations (typically, Auditory hallucination#Schizophrenia, hearing voices), delusions, thought disorder, disorganized thinking and behavior, and Reduced affect display, f ...
; in
cross-sectional studies
In statistics and econometrics, cross-sectional data is a type of data collected by observing many subjects (such as individuals, firms, countries, or regions) at a single point or period of time. Analysis of cross-sectional data usually consists ...
, 27 to 80 percent of patients with schizophrenia present with FTD. A hallmark feature of schizophrenia, it is also widespread amongst other
psychiatric disorders
A mental disorder, also referred to as a mental illness, a mental health condition, or a psychiatric disability, is a behavioral or mental pattern that causes significant distress or impairment of personal functioning. A mental disorder is ...
; up to 60 percent of those with
schizoaffective disorder
Schizoaffective disorder is a mental disorder characterized by symptoms of both schizophrenia (psychosis) and a mood disorder, either bipolar disorder or depression. The main diagnostic criterion is the presence of psychotic symptoms for at leas ...
and 53 percent of those with
clinical depression
Major depressive disorder (MDD), also known as clinical depression, is a mental disorder characterized by at least two weeks of pervasive low mood, low self-esteem, and loss of interest or pleasure in normally enjoyable activities. Intro ...
demonstrate FTD, suggesting that it is not exclusive to schizophrenia. About six percent of healthy subjects exhibit a mild form of FTD.
The
DSM-5-TR
The ''Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition'' (DSM-5), is the 2013 update to the ''Diagnostic and Statistical Manual of Mental Disorders'', the taxonomy (general), taxonomic and diagnostic tool published by the ...
mentions that less severe FTD may happen during the initial (prodromal) and residual periods of schizophrenia.
The characteristics of FTD vary amongst disorders. A number of studies indicate that FTD in
mania
Mania, also known as manic syndrome, is a Psychiatry, psychiatric Abnormality (behavior), behavioral syndrome defined as a state of Abnormality (behavior), abnormally elevated arousal, affect (psychology), affect, and energy level. During a mani ...
is marked by irrelevant intrusions and pronounced combinatory thinking, usually with a playfulness and flippancy absent from patients with schizophrenia.
The FTD present in patients with schizophrenia was characterized by disorganization,
neologism
In linguistics, a neologism (; also known as a coinage) is any newly formed word, term, or phrase that has achieved popular or institutional recognition and is becoming accepted into mainstream language. Most definitively, a word can be considered ...
, and fluid thinking, and confusion with word-finding difficulty.
There is limited data on the
longitudinal course of FTD. The most comprehensive longitudinal study of FTD by 2023 found a distinction in the longitudinal course of thought-disorder symptoms between schizophrenia and other psychotic disorders. The study also found an association between pre-index assessments of social, work and educational functioning and the longitudinal course of FTD.
Possible causes
Several theories have been developed to explain the causes of formal thought disorder. It has been proposed that FTD relates to
neurocognition
Neurocognitive functions are cognitive functions closely linked to the function of particular areas, neural pathways, or Cerebral cortex, cortical networks in the brain, ultimately served by the substrate of the brain's neurological matrix (i.e. a ...
via
semantic memory
Semantic memory refers to general world knowledge that humans have accumulated throughout their lives. This general knowledge (Semantics, word meanings, concepts, facts, and ideas) is intertwined in experience and dependent on culture. New concep ...
.
Semantic network
A semantic network, or frame network is a knowledge base that represents semantic relations between concepts in a network. This is often used as a form of knowledge representation. It is a directed or undirected graph consisting of vertices, ...
impairment in people with schizophreniameasured by the difference between fluency (e.g. the number of animals' names produced in 60 seconds) and phonological fluency (e.g. the number of words beginning with "F" produced in 60 seconds)predicts the severity of formal thought disorder, suggesting that verbal information (through
semantic priming) is unavailable.
Other
hypotheses
A hypothesis (: hypotheses) is a proposed explanation for a phenomenon. A scientific method, scientific hypothesis must be based on observations and make a testable and reproducible prediction about reality, in a process beginning with an educ ...
include
working memory
Working memory is a cognitive system with a limited capacity that can Memory, hold information temporarily. It is important for reasoning and the guidance of decision-making and behavior. Working memory is often used synonymously with short-term m ...
deficit (being confused about what has already been said in a conversation) and attentional focus.
FTD in schizophrenia has been found to be associated with structural and functional abnormalities in the language network, where structural studies have found bilateral
grey matter
Grey matter, or gray matter in American English, is a major component of the central nervous system, consisting of neuronal cell bodies, neuropil ( dendrites and unmyelinated axons), glial cells ( astrocytes and oligodendrocytes), synapses, ...
deficits; deficits in the bilateral
inferior frontal gyrus
The inferior frontal gyrus (IFG; also gyrus frontalis inferior) is the lowest positioned gyrus of the frontal gyri, of the frontal lobe, and is part of the prefrontal cortex.
Its superior border is the inferior frontal sulcus (which divides it ...
, bilateral
inferior parietal lobule
The inferior parietal lobule (subparietal district) lies below the horizontal portion of the intraparietal sulcus, and behind the lower part of the postcentral sulcus. Also known as Geschwind's territory after Norman Geschwind, an American neu ...
and bilateral
superior temporal gyrus
The superior temporal gyrus (STG) is one of three (sometimes two) gyri in the temporal lobe of the human brain, which is located laterally to the head, situated somewhat above the external ear.
The superior temporal gyrus is bounded by:
* the l ...
are FTD
correlates.
Other studies did not find an association between FTD and structural aberrations of the language network, however, and regions not included in the language network have been associated with FTD.
Future research is needed to clarify whether there is an association with FTD in schizophrenia and neural abnormalities in the language network.
Transmitter systems which might cause FTD have also been investigated. Studies have found that
glutamate
Glutamic acid (symbol Glu or E; known as glutamate in its anionic form) is an α-amino acid that is used by almost all living beings in the biosynthesis of proteins. It is a Essential amino acid, non-essential nutrient for humans, meaning that ...
dysfunction, due to a
rarefaction
Rarefaction is the reduction of an item's density, the opposite of compression. Like compression, which can travel in waves (sound waves, for instance), rarefaction waves also exist in nature. A common rarefaction wave is the area of low relati ...
of glutamatergic
synapse
In the nervous system, a synapse is a structure that allows a neuron (or nerve cell) to pass an electrical or chemical signal to another neuron or a target effector cell. Synapses can be classified as either chemical or electrical, depending o ...
s in the superior temporal gyrus in patients with schizophrenia, is a major cause of positive FTD.
The heritability of FTD has been demonstrated in a number of family and twin studies.
Imaging genetics studies, using a semantic verbal-fluency task performed by the participants during
functional MRI
Functional magnetic resonance imaging or functional MRI (fMRI) measures brain activity by detecting changes associated with blood flow. This technique relies on the fact that cerebral blood flow and neuronal activation are coupled. When an area o ...
scanning, revealed that
allele
An allele is a variant of the sequence of nucleotides at a particular location, or Locus (genetics), locus, on a DNA molecule.
Alleles can differ at a single position through Single-nucleotide polymorphism, single nucleotide polymorphisms (SNP), ...
s linked to glutamatergic transmission contribute to functional aberrations in typical language-related brain areas.
FTD is not solely
genetically determined, however; environmental influences, such as allusive thinking in parents during childhood, and environmental risk factors for schizophrenia (including childhood abuse, migration, social isolation, and
cannabis
''Cannabis'' () is a genus of flowering plants in the family Cannabaceae that is widely accepted as being indigenous to and originating from the continent of Asia. However, the number of species is disputed, with as many as three species be ...
use) also contribute to the pathophysiology of FTD.
The origins of FTD have been theorised from a
social-learning perspective. Singer and Wynne said that familial communication patterns play a key role in shaping the development of FTD; dysfunctional social interactions undermine a child's development of cohesive, stable mental representations of the world, increasing their risk of developing FTD.
Treatments
Antipsychotic
Antipsychotics, previously known as neuroleptics and major tranquilizers, are a class of Psychiatric medication, psychotropic medication primarily used to manage psychosis (including delusions, hallucinations, paranoia or disordered thought), p ...
medication is often used to treat FTD. Although the vast majority of studies of the efficacy of antipsychotic treatment do not report effects on syndromes or symptoms, six older studies report the effects of antipsychotic treatment on FTD. These studies and clinical experience indicate that antipsychotics are often an effective treatment for patients with positive or negative FTD, but not all patients respond to them.
Cognitive behavioural therapy
Cognitive behavioral therapy (CBT) is a form of psychotherapy that aims to reduce symptoms of various mental health conditions, primarily depression, PTSD, and anxiety disorders.
Cognitive behavioral therapy focuses on challenging and chang ...
(CBT) is another treatment for FTD, but its effectiveness has not been well-studied.
Large
randomised controlled trials
A randomized controlled trial (or randomized control trial; RCT) is a form of scientific experiment used to control factors not under direct experimental control. Examples of RCTs are clinical trials that compare the effects of drugs, surgical t ...
evaluating the effectiveness of CBT for treating psychosis often exclude individuals with severe FTD because it reduces the
therapeutic alliance
A therapeutic alliance, or working alliance, is a partnership between a patient and their therapist that allows them to achieve goals through agreed-upon tasks.
The concept of therapeutic alliance dates back to Sigmund Freud. Over the course of ...
required by the therapy.
However, provisional evidence suggests that FTD may not preclude the effectiveness of CBT.
Kircher and colleagues have suggested that the following methods should be used in CBT for patients with FTD:
*Practice structuring, summarizing, and feedback methods
*Repeat and clarify the core issues and main emotions that the patient is trying to communicate
*Gently encourage patients to clarify what they are trying to communicate
*Ask patients to clearly state their communication goal
*Ask patients to slow down and explain how one point leads to another
*Help patients identify the links between ideas
*Identify the main affect linked to the thought disorder
*Normalize problems with thinking
Signs and symptoms
Language abnormalities exist in the general population, and do not necessarily indicate a condition. They can occur in schizophrenia and other disorders (such as mania or depression), or in anyone who may be tired or stressed.
To distinguish thought disorder, patterns of speech, severity of symptoms, their frequency, and any resulting functional impairment can be considered.
Symptoms of FTD include
derailment
In rail transport, a derailment is a type of train wreck that occurs when a rail vehicle such as a train comes off its rails. Although many derailments are minor, all result in temporary disruption of the proper operation of the railway sys ...
,
pressured speech
Pressure of speech (or pressured speech) is a speech fast and frenetic (i.e., mainly without pauses), including some irregularities in loudness and rhythm or some degrees of circumstantiality; it is hard to interpret and expresses a feeling/ affect ...
,
poverty of speech,
tangentiality
Tangential speech or tangentiality is a communication disorder in which the train of thought of the speaker wanders and shows a lack of focus, never returning to the initial topic of the conversation.''Forensic Aspects of Communication Sciences and ...
, and
thought blocking.
The most common forms of FTD observed are tangentiality and circumstantiality. FTD is a hallmark feature of
schizophrenia
Schizophrenia () is a mental disorder characterized variously by hallucinations (typically, Auditory hallucination#Schizophrenia, hearing voices), delusions, thought disorder, disorganized thinking and behavior, and Reduced affect display, f ...
, but is also associated with other conditions that can cause psychosis (including
mood disorder
A mood disorder, also known as an affective disorder, is any of a group of conditions of mental and behavioral disorder where the main underlying characteristic is a disturbance in the person's mood. The classification is in the ''Diagnostic ...
s,
dementia
Dementia is a syndrome associated with many neurodegenerative diseases, characterized by a general decline in cognitive abilities that affects a person's ability to perform activities of daily living, everyday activities. This typically invo ...
,
mania
Mania, also known as manic syndrome, is a Psychiatry, psychiatric Abnormality (behavior), behavioral syndrome defined as a state of Abnormality (behavior), abnormally elevated arousal, affect (psychology), affect, and energy level. During a mani ...
, and
neurological diseases
Neurological disorders represent a complex array of medical conditions that fundamentally disrupt the functioning of the nervous system. These disorders affect the brain, spinal cord, and nerve networks, presenting unique diagnosis, treatment, and ...
).
Impaired
attention
Attention or focus, is the concentration of awareness on some phenomenon to the exclusion of other stimuli. It is the selective concentration on discrete information, either subjectively or objectively. William James (1890) wrote that "Atte ...
, poor
memory
Memory is the faculty of the mind by which data or information is encoded, stored, and retrieved when needed. It is the retention of information over time for the purpose of influencing future action. If past events could not be remembe ...
, and difficulty formulating abstract
concept
A concept is an abstract idea that serves as a foundation for more concrete principles, thoughts, and beliefs.
Concepts play an important role in all aspects of cognition. As such, concepts are studied within such disciplines as linguistics, ...
s may also reflect TD, and can be observed and assessed with mental-status tests such as
serial sevens or memory tests.
[ ''cited'' ]
Types
Thirty symptoms (or features) of TD have been described, including:
*
Alogia: A poverty of speech in amount or content, it is classified as a negative symptom of schizophrenia. When further classifying symptoms, poverty of speech content (little meaningful content with a normal amount of speech) is a disorganization symptom.
[
*"... In this way, alogia is conceived of as a 'negative thought disorder.' ..."
*"... The paucity of meaningful content in the presence of a normal amount of speech that is sometimes included in alogia is actually a disorganization of thought and not a negative symptom and is properly included in the disorganization cluster of symptoms. ..."] Under
SANS, thought blocking is considered a part of alogia, and so is increased latency in response.
*
Circumstantial speech
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.''Problem-Based Psychiatry'' by Ben Green ...
(also known as ''circumstantial thinking''):
[Houghtalen, Rory P; McIntyre, John S (2017). "7.1 Psychiatric Interview, History, and Mental Status Examination of the Adult Patient". In Sadock, Virginia A; Sadock, Benjamin J; Ruiz, Pedro (eds.). Kaplan & Sadock's Comprehensive Textbook of Psychiatry (10th ed.). Wolters Kluwer. HISTORY AND EXAMINATION, Thought Process/Form, Table 7.1–6. Examples of Disordered Thought Process/Form. . indicates and briefly defines the follow types: Clanging, Circumstantial, Derailment (loose associations), Flight of ideas, Incoherence (word salad), Neologism, Tangential, Thought blocking] An inability to answer a question without excessive, unnecessary or irrelevant detail. The point of the conversation is eventually reached, unlike in tangential speech.
A patient may answer the question "How have you been sleeping lately?" with "Oh, I go to bed early, so I can get plenty of rest. I like to listen to music or read before bed. Right now I'm reading a good mystery. Maybe I'll write a mystery someday. But it isn't helping, reading I mean. I have been getting only 2 or 3 hours of sleep at night."
*
Clanging
Clanging (or clang associations) is a symptom of mental disorders, primarily found in patients with schizophrenia and bipolar disorder. This symptom is also referred to as association chaining, and sometimes, glossomania.
Steuber defines it as "re ...
: An instance where ideas are related only by phonetics (similar or rhyming sounds) rather than actual meaning.
This may be heard as excessive rhyming or alliteration ("Many moldy mushrooms merge out of the mildewy mud on Mondays", or "I heard the bell. Well, hell, then I fell"). It is most commonly seen in the manic phase of
bipolar disorder
Bipolar disorder (BD), previously known as manic depression, is a mental disorder characterized by periods of Depression (mood), depression and periods of abnormally elevated Mood (psychology), mood that each last from days to weeks, and in ...
, although it is also often observed in patients with schizophrenia and
schizoaffective disorder
Schizoaffective disorder is a mental disorder characterized by symptoms of both schizophrenia (psychosis) and a mood disorder, either bipolar disorder or depression. The main diagnostic criterion is the presence of psychotic symptoms for at leas ...
.
*
Derailment
In rail transport, a derailment is a type of train wreck that occurs when a rail vehicle such as a train comes off its rails. Although many derailments are minor, all result in temporary disruption of the proper operation of the railway sys ...
(also known as ''loosening of associations'' and ''knight's move thinking''):
Thought frequently moves from one idea to another which is obliquely related or unrelated, often appearing in speech but also in writing ("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: In mid-speech, the subject is changed in response to a nearby stimulus ("Then I left San Francisco and moved to ... Where did you get that tie?")
*
Echolalia
Echolalia is the unsolicited repetition of vocalizations made by another person; when repeated by the same person, it is called palilalia. In its profound form it is automatic and effortless. It is one of the echophenomena, closely related to ...
:
[
* "Form of Thought. Disorders of the form of thought are objectively observable in patients' spoken and written language. The disorders include looseness of associations, derailment, incoherence, tangentiality, circumstantiality, neologisms, echolalia, verbigeration, word salad, and mutism."
* "Thought Process. ... Disorders of thought process include flight of ideas, thought blocking, impaired attention, poverty of thought content, poor abstraction abilities, perseveration, idiosyncratic associations (e.g., identical predicates and clang associations), overinclusion, and circumstantiality."
] Echoing of another's speech,
[ once or in repetition. It may involve repeating only the last few words (or the last word) of another person's sentences,] and is common on the autism spectrum
Autism, also known as autism spectrum disorder (ASD), is a neurodevelopmental disorder characterized by differences or difficulties in social communication and interaction, a preference for predictability and routine, sensory processing d ...
and in Tourette syndrome
Tourette syndrome (TS), or simply Tourette's, is a common neurodevelopmental disorder that begins in childhood or adolescence. It is characterized by multiple movement (motor) tics and at least one vocal (phonic) tic. Common tics are blinkin ...
.
*Evasion: The next logical idea in a sequence is replaced with another idea closely (but not accurately or appropriately) related to it; also known as ''paralogia'' and ''perverted logic''.
*Flight of ideas
This glossary covers terms found in the psychiatric literature; the word origins are primarily Greek, but there are also Latin, French, German, and English terms. Many of these terms refer to expressions dating from the early days of psychiatry i ...
: A form of FTD marked by abrupt leaps from one topic to another, possibly with discernible links between successive ideas, perhaps governed by similarities between subjects or by rhyming
A rhyme is a repetition of similar sounds (usually the exact same phonemes) in the final stressed syllables and any following syllables of two or more words. Most often, this kind of rhyming (''perfect rhyming'') is consciously used for a musica ...
, puns, wordplay, or innocuous environmental stimuli (such as the sound of birds chirping). It is most characteristic of the manic phase of bipolar disorder.
* Illogicality:[ includes and defines Derailment, Tangentiality, Incoherence, Illogicality, Circumstantiality, Pressure of speech, Distractible speech, Clanging.] Conclusions are reached which do not follow logically (non sequiturs or faulty inferences). "Do you think this will fit in the box?" is answered with, "Well of course; it's brown, isn't it?"
*Incoherence (word salad
A word salad is a "confused or unintelligible mixture of seemingly random words and phrases", most often used to describe a symptom of a neurological or mental disorder. The name schizophasia is used in particular to describe the confused langua ...
): Speech which is unintelligible because the individual words are real, but the manner in which they are strung together results in gibberish.[ 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!"
*]Neologism
In linguistics, a neologism (; also known as a coinage) is any newly formed word, term, or phrase that has achieved popular or institutional recognition and is becoming accepted into mainstream language. Most definitively, a word can be considered ...
s: Completely new words (or phrases) whose origins and meanings are usually unrecognizable ("I got so angry I picked up a dish and threw it at the geshinker"). They may also involve elision
In linguistics, an elision or deletion is the omission of one or more sounds (such as a vowel, a consonant, or a whole syllable) in a word or phrase. However, these terms are also used to refer more narrowly to cases where two words are run to ...
s of two words which are similar in meaning or sound. Although neologisms may refer to words formed incorrectly whose origins are understandable (such as "headshoe" for "hat"), these can be more clearly referred to as word approximations.
*Overinclusion: The failure to eliminate ineffective, inappropriate, irrelevant, extraneous details associated with a particular stimulus.[
* "This form of thought is most characteristic of mania and tends to be overinclusive, with difficulty in excluding irrelevant, extraneous details from the association."]
*Perseveration
Perseveration, in the fields of psychology, psychiatry, and speech–language pathology, is the repetition of a particular response (such as a word, phrase, or gesture) regardless of the absence or cessation of a stimulus. It is usually caused by ...
: Persistent repetition of words or ideas, even when another person tries to change the subject.[ ("It's great to be here in Nevada, Nevada, Nevada, Nevada, Nevada.") It may also involve repeatedly giving the same answer to different questions ("Is your name Mary?" "Yes." "Are you in the hospital?" "Yes." "Are you a table?" "Yes"). Perseveration can include palilalia and logoclonia, and may indicate an organic brain disease such as ]Parkinson's disease
Parkinson's disease (PD), or simply Parkinson's, is a neurodegenerative disease primarily of the central nervous system, affecting both motor system, motor and non-motor systems. Symptoms typically develop gradually and non-motor issues become ...
.
*Phonemic paraphasia
Paraphasia is a type of language output error commonly associated with aphasia and characterized by the production of unintended syllables, words, or phrases during the effort to speak. Paraphasic errors are most common in patients with fluent for ...
: Mispronunciation; syllables out of sequence ("I slipped on the lice and broke my arm").
*Pressured speech
Pressure of speech (or pressured speech) is a speech fast and frenetic (i.e., mainly without pauses), including some irregularities in loudness and rhythm or some degrees of circumstantiality; it is hard to interpret and expresses a feeling/ affect ...
: Rapid speech without pauses, which is difficult to interrupt.
* Referential thinking: Viewing innocuous stimuli as having a specific meaning for the self ("What's the time?" "It's 7 o'clock. That's my problem").
*Semantic paraphasia: Substitution of inappropriate words ("I slipped on the coat, on the ice I mean, and broke my book").
* Stilted speech: Speech characterized by words or phrases which are flowery, excessive, and pompous[ ("The attorney comported himself indecorously").
*]Tangential speech
Tangential speech or tangentiality is a communication disorder in which the train of thought of the speaker wanders and shows a lack of focus, never returning to the initial topic of the conversation.''Forensic Aspects of Communication Sciences and ...
: Wandering from the topic and never returning to it, or providing requested information ("Where are you from?" "My dog is from England. They have good fish and chips there. Fish breathe through gills").
* Thought blocking (also known as ''deprivation of thought'' and ''obstructive thought''): An abrupt stop in the middle of a train of thought which may not be able to be continued.
* Verbigeration:[ "Word salad describes the stringing together of words that seem to have no logical association, and verbigeration describes the disappearance of understandable speech, replaced by strings of incoherent utterances."] Meaningless, stereotyped repetition of words or phrases which replace understandable speech; seen in schizophrenia.
Terminology
Psychiatric and psychological glossaries in 2015 and 2017 defined ''thought disorder as disturbed thinking or cognition
Cognition is the "mental action or process of acquiring knowledge and understanding through thought, experience, and the senses". It encompasses all aspects of intellectual functions and processes such as: perception, attention, thought, ...
which affects communication
Communication is commonly defined as the transmission of information. Its precise definition is disputed and there are disagreements about whether Intention, unintentional or failed transmissions are included and whether communication not onl ...
, language
Language is a structured system of communication that consists of grammar and vocabulary. It is the primary means by which humans convey meaning, both in spoken and signed language, signed forms, and may also be conveyed through writing syste ...
, or thought content including poverty of ideas, neologisms
In linguistics, a neologism (; also known as a coinage) is any newly formed word, term, or phrase that has achieved popular or institutional recognition and is becoming accepted into mainstream language. Most definitively, a word can be considered ...
, paralogia, word salad
A word salad is a "confused or unintelligible mixture of seemingly random words and phrases", most often used to describe a symptom of a neurological or mental disorder. The name schizophasia is used in particular to describe the confused langua ...
, and delusion
A delusion is a fixed belief that is not amenable to change in light of conflicting evidence. As a pathology, it is distinct from a belief based on false or incomplete information, confabulation, dogma, illusion, hallucination, or some other m ...
s[
"thought disorder Any disturbance of thinking that affects language, communication, or thought content; the hallmark feature of schizophrenia. Manifestations range from simple blocking and mild circumstantiality to profound loosening of associations, incoherence, and delusions; characterized by a failure to follow semantic and syntactic rules that is inconsistent with the person's education, intelligence, or cultural background."] (disturbances of thought content and form), and suggested the more-specific terms content thought disorder (CTD) and formal thought disorder (FTD). CTD was defined as a TD characterized by multiple fragmented delusions,[
"''content thought disorder'' Disturbance in thinking in which a person exhibits delusions that may be multiple, fragmented, and bizarre."][ and FTD was defined as a disturbance in the form or structure of thinking.
The 2013 ]DSM-5
The ''Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition'' (DSM-5), is the 2013 update to the '' Diagnostic and Statistical Manual of Mental Disorders'', the taxonomic and diagnostic tool published by the American Psychiat ...
only used the term FTD, primarily as a synonym
A synonym is a word, morpheme, or phrase that means precisely or nearly the same as another word, morpheme, or phrase in a given language. For example, in the English language, the words ''begin'', ''start'', ''commence'', and ''initiate'' are a ...
for disorganized thinking and speech. This contrasts with the 1992 ICD-10
ICD-10 is the 10th revision of the International Classification of Diseases (ICD), a medical classification list by the World Health Organization (WHO). It contains codes for diseases, signs and symptoms, abnormal findings, complaints, social cir ...
(which only used the word "thought disorder", always accompanied with "delusion" and "hallucination")[
* F06.2 Organic delusional chizophrenia-likedisorder, p.59: Features suggestive of schizophrenia, such as bizarre delusions, hallucinations, or thought disorder, may also be present. ... ''Diagnostic guidelines'' ... Hallucinations, thought disorder, or isolated catatonic phenomena may be present. ...
* F20.0 Paranoid schizophrenia, p. 80: ... Thought disorder may be obvious in acute states, but if so it does not prevent the typical delusions or hallucinations from being described clearly. ...
* F20.1 Hebephrenic schizophrenia, p. 81: ... In addition, disturbances of affect and volition, and thought disorder are usually prominent. Hallucinations and delusions may be present but are not usually prominent. ...
] and a 2002 medical dictionary
A medical dictionary is a lexicon for words used in medicine. The four major medical dictionaries in the United States are ''Mosby's Dictionary of Medicine, Nursing & Health Professions'', ''Stedman's'', ''Taber's'', and Dorland's Medical Diction ...
which generally defined thought disorders similarly to the psychiatric glossaries and used the word in other entries as the ICD-10 did.
A 2017 psychiatric text describing thought disorder as a "disorganization syndrome" in the context of schizophrenia:
The text said that some clinician
A clinician is a health care professional typically employed at a skilled nursing facility or clinic. Clinicians work directly with patients rather than in a laboratory, community health setting or in research. A clinician may diagnose, treat a ...
s use the term "formal thought disorder" broadly, referring to abnormalities in thought form with psychotic cognitive signs or symptoms, and studies of cognition and subsyndromes in schizophrenia may refer to FTD as ''conceptual disorganization'' or ''disorganization factor''.
Some disagree:
Course, diagnosis, and prognosis
It was believed that TD occurred only in schizophrenia, but later findings indicate that it may occur in other psychiatric conditions (including mania) and in people without mental illness. Not all people with schizophrenia have a TD; the condition is not specific
Specific may refer to:
* Specificity (disambiguation)
* Specific, a cure or therapy for a specific illness
Law
* Specific deterrence, focussed on an individual
* Specific finding, intermediate verdict used by a jury in determining the final ...
to the disease.
When defining thought-disorder subtypes and classifying them as positive or negative symptoms, Nancy Andreasen found[ cited
*
*
*
]
that different subtypes of TD occur at different frequencies in those with mania, depression, and schizophrenia. People with mania have pressured speech as the most prominent symptom, and have rates of derailment, tangentiality, and incoherence as prominent as in those with schizophrenia. They are likelier to have pressured speech, distractibility, and circumstantiality.
People with schizophrenia have more negative TD, including poverty of speech and poverty of content of speech, but also have relatively high rates of some positive TD. Derailment, loss of goal, poverty of content of speech, tangentiality and illogicality are particularly characteristic of schizophrenia. People with depression have relatively-fewer TDs; the most prominent are poverty of speech, poverty of content of speech, and circumstantiality. Andreasen noted the diagnostic usefulness of dividing the symptoms into subtypes; negative TDs without full affective symptoms suggest schizophrenia.
She also cited the prognostic value of negative-positive-symptom divisions. In manic patients, most TDs resolve six months after evaluation; this suggests that TDs in mania, although as severe as in schizophrenia, tend to improve. In people with schizophrenia, however, negative TDs remain after six months and sometimes worsen; positive TDs somewhat improve. A negative TD is a good predictor of some outcomes; patients with prominent negative TDs are worse in social functioning six months later. More prominent negative symptoms generally suggest a worse outcome; however, some people may do well, respond to medication, and have normal brain function. Positive symptoms vary similarly.
A prominent TD at illness onset suggests a worse prognosis, including:
* illness begins earlier
* increased risk of hospitalization
* decreased functional outcomes
* increased disability rates
* increased inappropriate social behaviors
TD which is unresponsive to treatment predicts a worse illness course. In schizophrenia, TD severity tends to be more stable than hallucinations and delusions. Prominent TDs are more unlikely to diminish in middle age, compared with positive symptoms. Less-severe TD may occur during the prodromal
In medicine, a prodrome is an early Medical sign, sign or symptom (or set of signs and symptoms, referred to as prodromal symptoms) that often indicates the onset of a disease before more diagnostically specific signs and symptoms develop. More spe ...
and residual periods of schizophrenia. Treatment for thought disorder may include psychotherapy, such as cognitive behavior therapy (CBT), and psychotropic medications.
The DSM-5
The ''Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition'' (DSM-5), is the 2013 update to the '' Diagnostic and Statistical Manual of Mental Disorders'', the taxonomic and diagnostic tool published by the American Psychiat ...
includes delusions, hallucinations, disorganized thought process (formal thought disorder), and disorganized or abnormal motor behavior (including catatonia
Catatonia is a complex syndrome most commonly seen in people with underlying mood disorders, such as major depressive disorder, or psychotic disorders, such as schizophrenia. People with catatonia exhibit abnormal movement and behaviors, wh ...
) as key symptoms of psychosis. Schizophrenia-spectrum disorders such as schizoaffective disorder and schizophreniform disorder typically consist of prominent hallucinations, delusions and FTD; the latter presents as severely disorganized, bizarre, and catatonic behavior. Psychotic disorders due to medical conditions and substance use typically consist of delusions and hallucinations. The rarer delusional disorder and shared psychotic disorder typically present with persistent delusions. FTDs are commonly found in schizophrenia and mood disorders, with poverty of speech content more common in schizophrenia.
Psychoses such as schizophrenia and bipolar mania are distinguishable from malingering
Malingering is the fabrication, feigning, or exaggeration of physical or psychological symptoms designed to achieve a desired outcome, such as personal gain, relief from duty or work, avoiding arrest, receiving medication, or mitigating prison se ...
, when an individual fakes illness for other gains, by clinical presentations; malingerers feign thought content with no irregularities in form such as derailment or looseness of association. Negative symptoms, including alogia, may be absent, and chronic thought disorder is typically distressing.
Autism spectrum disorders (ASD) whose diagnosis requires the onset of symptoms before three years of age can be distinguished from early-onset schizophrenia; schizophrenia under age 10 is extremely rare, and ASD patients do not display FTDs. However, it has been suggested that individuals with 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 parent reports of stress and anxiety.
Rorschach test
The Rorschach test is a projective test, projective psychological test in which subjects' perceptions of inkblots are recorded and then analyzed using psychology, psychological interpretation, complex algorithms, or both. Some psychologists u ...
s have been useful for assessing TD in disturbed patients. A series of inkblots are shown, and patient responses are analyzed to determine disturbances of thought. The nature of the assessment offers insight into the cognitive processes of another, and how they respond to equivocal stimuli. Hermann Rorschach developed this test to diagnose schizophrenia after realizing that people with schizophrenia gave drastically different interpretations of Klecksographie inkblots from others whose thought processes were considered normal, and it has become one of the most widely used assessment tools for diagnosing TDs.
The Thought Disorder Index (TDI), also known as the Delta Index, was developed to help further determine the severity of TD in verbal responses. TDI scores are primarily derived from verbally-expressed interpretations of the Rorschach test, but TDI can also be used with other verbal samples (including the Wechsler Adult Intelligence Scale
The Wechsler Adult Intelligence Scale (WAIS) is an IQ test designed to measure intelligence and cognitive ability in adults and older adolescents. For children between the ages of 6 and 16, Wechsler Intelligence Scale for Children (WISC) is com ...
). TDI has a twenty-three-category scoring index; each category scores the level of severity on a scale from 0 to 1, with .25 being mild and 1.00 being most severe (0.25, 0.50, 0.75, 1.00).
Criticism
TD has been criticized as being based on circular or incoherent definitions.[ Bentall, R. (2003) ''Madness explained: Psychosis and Human Nature''. London: Penguin Books Ltd. ] Symptoms of TD are inferred from disordered speech, based on the assumption that disordered speech arises from disordered thought. Although TD is typically associated with psychosis, similar phenomena can appear in different disorders and leading to misdiagnosis.
A criticism related to the separation of symptoms of schizophrenia into negative or positive symptoms, including TD, is that it oversimplifies the complexity of TD and its relationship to other positive symptoms. Factor analysis
Factor analysis is a statistical method used to describe variability among observed, correlated variables in terms of a potentially lower number of unobserved variables called factors. For example, it is possible that variations in six observe ...
has found that negative symptoms tend to correlate with one another, but positive symptoms tend to separate into two groups.[ ''cited''
*
*
*
] The three clusters became known as negative symptoms, psychotic symptoms, and disorganization symptoms. Alogia, a TD traditionally classified as a negative symptom, can be separated into two types: poverty of speech content (a disorganization symptom) and poverty of speech, response latency, and thought blocking (negative symptoms).
Positive-negative-symptom diametrics, however, may enable a more accurate characterization of schizophrenia.[ "The two-syndrome concept as formulated by T. J. Crow was especially important in spurring research into the nature of negative symptoms ... but this does not diminish the creative efforts that led to these scales or importance of these scales for research. In fact, it was only through careful analysis of the structure of symptoms in these scales that a more accurate characterization of the phenomenology of schizophrenia was possible."
]
See also
* Aphasia
Aphasia, also known as dysphasia, is an impairment in a person's ability to comprehend or formulate language because of dysfunction in specific brain regions. The major causes are stroke and head trauma; prevalence is hard to determine, but aph ...
* Auditory processing disorder
Auditory processing disorder (APD) is a neurodevelopmental disorder affecting the way the brain processes sounds. Individuals with APD usually have normal structure and function of the ear, but cannot process the information they hear in the s ...
* Emil Kraepelin's dream speech
* Speech–language pathology
Speech–language pathology, also known as speech and language pathology or logopedics, is a healthcare and academic discipline concerning the evaluation, treatment, and prevention of communication disorders, including expressive and mixed ...
References
Sources
*
*
*
*
*
{{DEFAULTSORT:Thought Disorder
Psychosis
*