Factor structure of the Greek translation of the Scale for the Assessment of Thought, Language and Communication

Evidence for the factor structure of formal thought disorder: A systematic review

Disorganised speech, or, formal thought disorder (FTD), is considered one of the core features of psychosis, yet its factor structure remains debated. This systematic review aimed to identify the core dimensions of FTD. In line with the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA), a systematic review was conducted on the FTD factor analytic literature. Sixteen studies were identified from PsycINFO, PubMed and Web of Science between October 1971 and January 2023. Across the 39 factor analyses investigated, findings demonstrated the prominence of a three-factor structure. Broad agreement was found for two factors within the three-factor model, which were typically referred to as disorganisation and negative, with the exact nature of the third dimension requiring further clarification. The quality assessment revealed some methodological challenges relating to the assessment of FTD and conducted factor analyses. Future research should clarify the exact nature of the third dimension across different patient groups and methodologies to determine whether a consistent transdiagnostic concept of FTD can be elucidated.

Auditory processing disorder may be present in schizophrenia and it is highly correlated with formal thought disorder

The present study investigates the presence of Auditory Processing Disorder (APD) in schizophrenia and its association with symptomatology, especially Formal Thought Disorder (FTD). 50 patients with schizophrenia and 25 matched healthy controls completed a battery of three auditory processing tests. Positive and Negative Syndrome Scale (PANSS) and Thought, Language and Communication (TLC) scale were used to assess clinical symptoms. The patient group was divided into two subgroups, according to FTD severity. Auditory processing performance of the control group and the patient group was evaluated. Correlations between auditory processing scores and TLC scores, as well as auditory processing scores and PANSS scores were examined. Most of the patients, especially those with FTD, had auditory deficits that can be classified as APD. Patients showed impaired performance compared to controls in all tests. Total severity and specific factors of FTD, as well as other clinical symptoms and symptom categories were correlated with auditory processing performance. We provided evidence that APD may be present in schizophrenia and that FTD, as well as other clinical symptoms are associated with auditory processing deficits. There are important clinical implications for non-pharmacological interventions and early diagnosis of schizophrenia.

"Formal Thought Disorder" in a General-Community Sample With Elevated Schizotypal Traits

Different dimensions of formal thought disorder (FTD) are distinguished by different patterns of cognitive dysfunction and cortical variability in patients with schizophrenia; however, inconsistent findings may relate to patient-related confounds. Investigating FTD in nonpatient samples with elevated levels of schizotypal traits avoids these confounds, but its utility to FTD research is unknown. Thus, we performed principal components analysis (PCA) of FTD ratings using the Scale for the Assessment of Thought, Language, and Communication (TLC) and the Thought and Language Index (TLI) in a general-community sample with elevated schizotypal traits. Both scales showed "clinically elevated" FTD, particularly, the TLC. PCA described a three-component TLC solution ("disorganization," "verbosity," "emptiness") and a two-component TLI solution ("negative," "idiosyncratic"), generally consistent with schizophrenia research. TLC "disorganization" and "emptiness" were correlated with psychosis-like experiences. TLI "negative" was associated with lower general cognitive function, consistent with schizophrenia research. FTD may have shared etiology along the schizophrenia spectrum.

Psychotropic drug-prescribing correlates of disorganized speech in Asians with schizophrenia: The REAP-AP study

BACKGROUND

Although disorganized speech is seen as one of the nuclear features of schizophrenia, there have been few reports of disorganized speech-associated psychotropic drug-prescribing patterns in large samples of schizophrenia patients.

OBJECTIVE

We aimed to examine the prevalence of disorganized speech and its correlates in terms of psychotropic drug prescribing, using the data from the Research on Asian Psychotropic Patterns for Antipsychotics (REAP-AP) study.

METHOD

A total of 3744 patients with the ICD-10 diagnosis of schizophrenia were enrolled from 71 survey centers in 15 Asian countries/areas. An essential criterion of disorganized speech was that it was "severe enough to impair substantially effective communication" as defined in the DSM-5. A binary logistic model was fitted to identify the psychotropic drug-prescribing correlates of disorganized speech.

RESULTS

After adjusting for the potential effects of confounding variables, the binary logistic regression model showed that the presence of disorganized speech was directly associated with adjunctive use of mood stabilizers (P < 0.001) and cumulative diazepam equivalent dose (P < 0.0001), and inversely associated with adjunctive use of anti-Parkinson drugs (P < 0.0001).

CONCLUSION

The association between disorganized speech and adjunctive use of mood stabilizers could perhaps be understood in the context of a relationship with impulsiveness/aggressiveness, or in terms of deconstructing the Kraepelinian dualism.

Reliability and validity of the Korean version of the Scale for the Assessment of Thought, Language, and Communication

BACKGROUND

Our study aimed to assess the inter-rater and test-retest reliability, as well as concurrent and convergent validity, of the Korean version of the Scale for the Assessment of Thought, Language, and Communication (TLC scale).

METHODS

The factor solutions and psychometric properties of the Korean version of the TLC scale were evaluated among 167 schizophrenia inpatients (study subjects) at two sites in South Korea. Using Pearson's correlation, the concurrent and convergent validities of each of the factor solutions were represented by the correlations with the scores on the Clinical Language Disorder Rating Scale, Brief Psychiatric Rating Scale, Young Mania Rating Scale, and Calgary Depression Scale. Using receiver operating characteristics curves, the optimal cut-off score for the Korean version of the TLC scale to distinguish between study subjects with and without disorganized speech, was identified.

RESULTS

The results showed that the Korean version of the TLC scale has a three-factor solution: fluent disorganization, speech emptiness, and speech peculiarity. In addition, the interrater reliability of the Korean version of the TLC scale was moderately good (intraclass correlation coefficient = 0.51) and its test-retest reliability was very good (Pearson's correlation coefficient = 0.94). For detecting the current presence of disorganized speech, the optimal cut-off total score on the TLC scale was proposed to be 8 points (sensitivity = 88.1%; specificity = 82.9%).

LIMITATIONS

Psychometric tools covering cognitive functions were not used in our study.

CONCLUSIONS

The Korean version of the TLC scale is a promising psychometric method for examining formal thought disorder (FTD) and disorganized speech in schizophrenia patients.

The Epidemiology and Associated Phenomenology of Formal Thought Disorder: A Systematic Review

BACKGROUND

Authors of the Diagnostic and Statistical Manual, Fifth Edition (DSM-V) have recommended to "integrate dimensions into clinical practice." The epidemiology and associated phenomenology of formal thought disorder (FTD) have been described but not reviewed. We aimed to carry out a systematic review of FTD to this end.

METHODS

A systematic review of FTD literature, from 1978 to 2013, using Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines.

RESULTS

A total of 881 abstracts were reviewed and 120 articles met inclusion criteria; articles describing FTD factor structure (n = 15), prevalence and longitudinal course (n = 41), role in diagnosis (n = 22), associated clinical variables (n = 56), and influence on outcome (n = 35) were included. Prevalence estimates for FTD in psychosis range from 5% to 91%. Dividing FTD into domains, by factor analysis, can accurately identify 91% of psychotic diagnoses. FTD is associated with increased clinical severity. Poorer outcomes are predicted by negative thought disorder, more so than the typical construct of "disorganized speech."

CONCLUSION

FTD is a common symptom of psychosis and may be considered a marker of illness severity. Detailed dimensional assessment of FTD can clarify diagnosis and may help predict prognosis.

A rating scale for the assessment of objective and subjective formal Thought and Language Disorder (TALD)

Formal thought disorder (FTD) is a core syndrome of schizophrenia. However, patients with other diagnoses, such as mania and depression amongst others, also present with FTD. We introduce a novel, comprehensive clinical rating scale, capturing the full variety of FTD phenomenology including subjective experiences. The 30-item Thought and Language Disorder (TALD) scale is based on a detailed review of the literature, encompassing all formal thought disorder symptoms reported from the early 20th century onwards. Objectively observable symptoms as well as subjective phenomena were included. Two hundred and ten participants (146 patients ICD-10 diagnoses: depression n=63, schizophrenia n=63, mania n=20; 64 healthy control subjects) were interviewed and symptoms rated with the TALD, TLC, HAMD, YMRS and SAPS/SANS. A principal component analyses was performed for the TALD to differentiate sub-syndromes. The principal component analysis revealed four FTD factors; objective and subjective as well as positive and negative factor dimensions. The correlation analyses with the TLC and the SAPS/SANS FTD sub-scores demonstrated the factor validity for the objective factors. The different diagnoses showed a distinct pattern of symptom severity in each of the factors, with mania patients exhibiting the highest value in the positive, objective dimension. The scale showed good psychometric results, which makes it a practicable, nosologically-open instrument for the detailed assessment of all FTD dimensions. The results strengthen the importance of subjective symptom assessment reported by the patient.

Semantic priming in remitted patients with bipolar disorder

BACKGROUND AND OBJECTIVES

Semantic priming disturbances are increasingly recognized as a feature of schizophrenia, and increased priming has been suggested to constitute a "cognitive correlate" of positive formal thought disorder (FTD). The present study aimed to investigate semantic priming in patients with bipolar disorder (BD).

METHODS

A primed lexical decision task with strongly related (STR), weakly related (WR), or unrelated (UR) prime-target pairs (SOA = 250 ms) was administered to fourteen remitted patients with BD and twelve control subjects matched on key demographic variables. FTD was measured by means of the Scale for Thought, Language and Communication (TLC).

RESULTS

Control subjects showed a robust (59.6 ms) and statistically significant priming effect for STR words, while priming for UR words was non-significant. In patients there was no evidence of priming in either condition. In patients, there were no significant correlations between priming magnitude and TLC scores. However, the only patient with a positive score on the TLC disorganization factor exhibited evidence of hyperpriming.

LIMITATIONS

The present patient sample exhibited very low TLC scores, and no direct comparison to patients with schizophrenia was possible.

CONCLUSIONS

The finding of decreased priming in patients with BD raises the possibility that semantic processing abnormalities in BD are of a different nature than those encountered in schizophrenia. Due to the small size and very low TLC scores of the present patient sample, no definite conclusions can be drawn as to the relationship of formal thought disorder and semantic processing abnormalities in BD.

The German translation and validation of the scale for the assessment of thought, language and communication: a factor analytic study

The Scale for the Assessment of Thought, Language and Communication (TLC) represents an instrument for the assessment of formal thought disorder (FTD). The factorial dimensionality of the TLC has yielded ambiguous results for a distinction between positive (e.g. circumstantiality) and negative (e.g. poverty of speech) FTD. The purpose of the current study was to first translate and validate the TLC scale in German. Second, the internal structure was explored in order to identify different FTD dimensions. Two hundred and ten participants (146 patients with ICD-10 diagnoses: depression n = 63, schizophrenia n = 63, mania n = 20; 64 healthy subjects) were interviewed and FTD was rated with the TLC. The principal component analysis of the German TLC version revealed a 3-factor solution, reflecting a disorganized factor, an emptiness factor and a linguistic control factor. The current investigation yielded similar results to those originally reported for the TLC. Thus, a distinction between a positive disorganized, a negative and a semantic word level factor can be supported for the German translation.