Subclinical thought disorder in first-degree relatives of schizophrenic patients. Results from a matched-pairs study with the Thought Disorder Index

The psychopathology among the offspring of schizophrenia and bipolar I disorder patients in an Egyptian sample: A comparative study

BACKGROUND

A variety of psychiatric illnesses can develop in children of parents who suffer from bipolar affective disorder.

AIMS

The purpose of the research was to investigate, among the offsprings of patients diagnosed with schizophrenia and bipolar disorder type I, the prevalence of a variety of psychiatric diseases as well as a range of behavioral abnormalities.

METHOD

This was a cross-sectional observational comparative study. The outpatient psychiatric clinics at Shebin Elkom Mental Health Hospital, Menofia Governorate, Egypt 500 offspring (there were 250 offspring of parents both diagnosed with schizophrenia and 250 offsprings born to parents with bipolar affective disorder).

RESULTS

Statistically significant association of male gender with somatic complaints, social problems, and attention problems in the bipolar offspring group. In addition, there was a statistically significant association between female gender and anxiety or depression in the bipolar offspring group. Moreover, there was a statistically significant association between male gender and thought problems and aggressive behavior in the schizophrenia group. Assessment of psychiatric symptoms using K-SADS in relation to gender revealed a statistically significant association of male gender with affective disorder, behavioral disorder, and substance use disorder in the bipolar offspring group. Moreover, there was a statistically significant association between female gender and psychotic disorder in the schizophrenia group.

CONCLUSION

We concluded that offspring with bipolar illness had a significant association with somatic symptoms, anxiety/depressive disorder, social issues, attention problems, and aggressive behavior. Schizophrenia offspring were strongly related to thought issues.

Higher-order language dysfunctions as a possible neurolinguistic endophenotype for schizophrenia: Evidence from patients and their unaffected first degree relatives

The purpose of the study was to examine the presence of pragmatic dysfunctions in first episode (FE) subjects and their healthy first degree relatives as a potential endophenotype for schizophrenia. Thirty-four FE patients, 34 parents of the patients (REL) and 32 healthy controls (HC) took part in the study. Pragmatic language functions were evaluated with the Right Hemisphere Language Battery, attention and executive functions were controlled, as well as age and education level. The parents differed from HC but not from their FE offspring with regard to overall level of language and communication and the general knowledge component of language processing. The FE participants differed from HC in comprehension of inferred meaning, emotional prosody, discourse dimensions, overall level of language and communication, language processing with regard to general knowledge and communication competences. The FE participants differed from REL regarding discourse dimensions. Our findings suggest that pragmatic dysfunctions may act as vulnerability markers of schizophrenia; their assessment may help in the diagnosis of early stages of the illness and in understanding its pathophysiology. In future research the adoptive and biological parents of schizophrenia patients should be compared to elucidate which language failures reflect genetic vulnerability and which ones environmental factors.

Rethinking Thought Disorder

It has been 30 years since Holzman introduced a special issue of the Schizophrenia Bulletin entitled “Thought Disorder in Schizophrenia.” He pointed out in his Editor’s Introduction that in contrast to the explosion of interest at that time in the biological aspects of schizophrenia, there were important areas of study that represented “... relatively neglected aspects of the psychopathology of schizophrenia, namely the varieties of thinking disorders (emphasis added) characteristic of schizophrenic patients and their possible underlying mechanisms.” Perhaps presciently, he ended his introduction by expressing hope that the articles included in that issue would lead to further intensive study of the cognitive (emphasis added) dysfunctions in schizophrenia. There has, indeed, been extensive research conducted in further understanding cognitive dysfunctions in schizophrenia, but considerably less so in understanding thought disorder.

Thought Disorder in Schizophrenia and Bipolar Disorder Probands, Their Relatives, and Nonpsychiatric Controls

Thought disorder (TD) has long been associated with schizophrenia (SZ) and is now widely recognized as a symptom of mania and other psychotic disorders as well. Previous studies have suggested that the TD found in the clinically unaffected relatives of SZ, schizoaffective and bipolar probands is qualitatively similar to that found in the probands themselves. Here, we examine which quantitative measures of TD optimize the distinction between patients with diagnoses of SZ and bipolar disorder with psychotic features (BP) from nonpsychiatric controls (NC) and from each other. In addition, we investigate whether these same TD measures also distinguish their respective clinically unaffected relatives (RelSZ, RelBP) from controls as well as from each other. We find that deviant verbalizations are significantly associated with SZ and are co-familial in clinically unaffected RelSZ, but are dissociated from, and are not co-familial for, BP disorder. In contrast, combinatory thinking was nonspecifically associated with psychosis, but did not aggregate in either group of relatives. These results provide further support for the usefulness of TD for identifying potential non-penetrant carriers of SZ-risk genes, in turn enhancing the power of genetic analyses. These findings also suggest that further refinement of the TD phenotype may be needed in order to be suitable for use in genetic studies of bipolar disorder.

Thought disorder in mid-childhood as a predictor of adulthood diagnostic outcome: findings from the New York High-Risk Project

BACKGROUND

Thought disorder has been proposed as an indicator of schizotypy, which is considered to be necessary but not sufficient for the development of schizophrenia. It is unclear whether thought disorder is an indicator of susceptibility (i.e. an endophenotype) for schizophrenia. The goal of the present study was to elucidate the role of thought disorder in relation to schizotypy by examining its presence in high-risk individuals during mid-childhood. Method The sample consisted of 265 subjects drawn from the New York High-Risk Project. Individuals at high risk for schizophrenia (i.e. offspring of parents with schizophrenia) were compared with individuals at low risk for schizophrenia (i.e. offspring of parents with affective disorder or offspring of psychiatrically normal parents). Videotaped interviews were rated for thought disorder using the Scale for the Assessment of Thought, Language, and Communication (TLC). The same subjects were administered diagnostic interviews in late adolescence/early adulthood.

RESULTS

Although positive thought disorder was equally present in subjects with affective and non-affective psychoses, negative thought disorder (namely, poverty of speech and poverty of content of speech) was elevated only in subjects with schizophrenia-related psychosis. Logistic regression analyses revealed that negative thought disorder added to the prediction of schizophrenia-related psychosis outcomes over and above positive thought disorder.

CONCLUSIONS

These findings suggest that negative thought disorder may have a specific association with schizotypy, rather than a more general association with psychosis. The findings also support consideration of negative thought disorder as an endophenotypic indicator of a schizophrenia diathesis.

Frequency of normative word associations in the speech of individuals at familial high-risk for schizophrenia

The intrusion of associations into speech in schizophrenia disrupts coherence and comprehensibility, a feature of formal thought disorder referred to as loosened associations. We have previously proposed that loosened associations may result from hyperactivity in semantic association networks, leading to an increased frequency of associated words appearing in speech. Using Computed Associations in Sequential Text (CAST) software to quantify the frequency of such associations in speech, we have reported more frequent normative associations in language samples from patients with schizophrenia and in individuals with schizotypal characteristics. The present study further examined this deviance in schizophrenia by studying normative associations in those who share genes with an individual with schizophrenia, (i.e. first-degree relatives of probands with schizophrenia; HR) but who do not have an illness. Familial high-risk participants (n=22), and controls (n=24) provided verbal responses to cards from the Thematic Apperception Test. CAST analysis revealed that HR used more associated words in their speech compared to controls. Furthermore, the frequency of normative word associations was positively correlated with dimensional and total scores of schizotypy derived from ratings of the structured interview for schizotypy, which confirms past research showing a relationship between schizotypy and hyperassociations. Our results suggest that some language disturbances in schizophrenia likely arise from an underlying psychopathological mechanism, hyperactivity of semantic associations.

Thought disorder in offspring of schizophrenic parents: findings from the New York High-Risk Project

The goal of the present analyses was to examine the hypothesis that mild forms of thought disorder (TD) may serve as an indicator of genetic liability for schizophrenia. A subset of 232 subjects drawn from the New York High-Risk Project was used to compare individuals at high risk for schizophrenia (ie, offspring of parents with schizophrenia; n = 63) with 2 groups of individuals at low risk for schizophrenia (ie, offspring of parents with affective disorder [n = 52] and offspring of psychiatrically normal parents [n = 117]). Subjects were administered the Rorschach Inkblot Test, and their responses were assessed according to the Thought Disorder Index (TDI). The high-risk offspring displayed significantly more TD than the other 2 groups, as shown by significantly higher TDI scores. Moreover, they had more deviant verbalizations, according to their significantly higher scores on a composite Idiosyncratic Verbalizations score. As expected, the offspring who developed psychosis produced more TD in adolescence than those who did not develop psychosis. In the sample as a whole, TD scores during late adolescence/early adulthood were positively associated with schizotypal features during mid-adulthood. These findings support the assertion that the presence of TD serves as an endophenotypic marker of a schizophrenia diathesis.

The Genetic Basis of Thought Disorder and Language and Communication Disturbances in Schizophrenia

Thought disorder as well as language and communication disturbances are associated with schizophrenia and are over-represented in clinically unaffected relatives of schizophrenics. All three kinds of dysfunction involve some element of deviant verbalizations, most notably, semantic anomalies. Of particular importance, thought disorder characterized primarily by deviant verbalizations has a higher recurrence in relatives of schizophrenic patients than schizophrenia itself. These findings suggest that deviant verbalizations may be more penetrant expressions of schizophrenia susceptibility genes than schizophrenia. This paper reviews the evidence documenting the presence of thought, language and communication disorders in schizophrenic patients and in their first-degree relatives. This familial aggregation potentially implicates genetic factors in the etiology of thought disorder, language anomalies, and communication disturbances in schizophrenia families. We also present two examples of ways in which thought, language and communication disorders can enrich genetic studies, including those involving schizophrenia.

Thought Disorder Index: a longitudinal study of severity levels and schizophrenia factors

BACKGROUND

Thought disturbances are commonly associated with psychiatric disorders, especially schizophrenia. Our aim was to clarify whether thought disorders are only stable at certain severity levels and in the presence of certain schizophrenia factors of the Thought Disorder Index (TDI) scale. Furthermore, we also examined the significance of genetic status and the psychiatric disorder for the persistence of TDI severity levels and factors.

METHODS

The thought disorders of 158 adoptees genetically at high-risk or low-risk for schizophrenia participating the Finnish Adoptive Family Study of Schizophrenia were evaluated twice at a mean interval of 11 years. Thought Disorder Index (TDI) was used to assess the severity levels and schizophrenia factors. TDI identifies 23 different items of thinking disturbances, which are weighted along a continuum of severity.

RESULTS

Thought disorders at the 0.50 and 0.75 severity levels and idiosyncratic verbalization indicative of the schizophrenia factors turned out to be stable phenomena throughout the follow-up period. The adoptees' genetic or psychiatric status was not associated with the results.

CONCLUSIONS

The study shows that the stability of TDI seems to be related to the most severe categories of thought disorders. However, of the specific schizophrenia factors, idiosyncratic verbalization, but not confusion and fluid thinking, showed stability over time. Although idiosyncratic verbalization does not necessarily represent the most severe type of thought disturbance, it turned out relatively stable and we can speculate that idiosyncratic verbalization have some predictive value, too.

Thinking within the spectrum: schizophrenic thought disorder in six Danish pedigrees

Formal thought disorder (FTD), a major symptom of schizophrenia, is known to aggregate in families. Our aim was to examine the specificity of FTD in the schizophrenia spectrum disorders and the hypothesized linear aggregation of FTD within pedigrees. Six individuals with a diagnosis of schizophrenia were identified in the Copenhagen High-Risk study and each pedigree was centered on one of the six original schizophrenic probands' nuclear families. The 329 pedigree members in the study were considered at risk for schizophrenia spectrum disorders because most were genetically related to the originating schizophrenic probands. The participants were administered the Copenhagen Interview of Functional Illness to determine diagnoses and the Thought Disorder Index (TDI) was used to assess FTD. Individuals with a schizophrenia diagnosis had higher global levels of FTD, exhibited more severe types of FTD, and had a qualitatively different type of FTD than did participants with other diagnoses or no mental illness. Individuals with Cluster A diagnoses exhibited more FTD and FTD similar in quality to participants with schizophrenia. These results support the construct of a spectrum of schizophrenia conditions. There was a generally high level of FTD in the pedigrees, in part due to assortative mating in this sample. However, there was no apparent pattern of linear aggregation of FTD within the families.

Early presence of thought disorder as a prospective sign of mental disorder

The purpose of this study was to assess whether premorbid signs, such as thought disorder, could predict the subsequent manifestation of psychiatric disorders. A group of 75 adoptees at high genetic risk for schizophrenia and 96 low-risk adoptees without any psychiatric disorder at the initial assessment were assessed blindly with the Thought Disorder Index (TDI). Their psychiatric status was re-assessed according to DSM-III-R criteria in a re-interview 11 years later and based on available registers 16 years later. High scores on several TDI variables at the initial assessment predicted a psychiatric disorder of all adoptees at follow-up. Prediction was statistically unsuccessful among the high-risk adoptees because of the small number of cases, but high scores at the 0.50 severity level did predict mental disorders among the low-risk adoptees.

Behavioral science foundations of the Rorschach test: research and clinical applications

Never without its critics, the Rorschach Test continues to be widely used in clinical settings. The test continues to be criticized vigorously. Rorschach critics appear to fall into two broad groups: those leveling valid methodological concerns about the test s behavioral science foundations and method critics who appear to deny the validity of the test on strictly a priori or theoretical considerations. Many critics do not appear to be acquainted with the extensive Rorschach research literature. The current paper provides an overview of several domains of applied and laboratory Rorschach behavioral science, including statistical power analysis, interobserver agreement and interrater reliability, Rorschach assessment of thought disorder, and emerging research linking Rorschach variables with diagnostic criteria from the DSM-IV, as a means of educating both adherents and detractors alike concerning the test s scientific track record and applicability to clinical assessment.

From predisposition to psychosis: progression of symptoms in schizophrenia

Schizophrenia is increasingly viewed as a neurodevelopmental process caused by an interaction between genetic factors and environmental stressors. Prospective studies and retrospective research using objective data indicate that behavioural deviations can be dated to early infancy and cut across multiple behavioural domains. In adolescence, preschizophrenics exhibit subtle changes in cognition and affect as well as a variety of anomalous subjective experiences (so-called 'basic symptoms'), suggesting 'trait' status of these features. Prodromal symptoms occur in a substantial proportion of preschizophrenics, followed by a short prepsychotic phase with the crystallization of a psychotic syndrome. Clinical, phenomenological and conceptual aspects of these early preschizophrenic phases are reviewed, and their neurobiological implications are briefly addressed. It is concluded that there is an urgent need for detailed and multidisciplinary prospective studies, but that the evidence accumulated to date is sufficient to justify research-based secondary prevention programmes.

Hippocampal N-acetyl aspartate in unaffected siblings of patients with schizophrenia: a possible intermediate neurobiological phenotype

BACKGROUND

Shared neurobiological characteristics of patients with schizophrenia and their siblings may represent "intermediate phenotypes" that may more closely reflect the genetic susceptibility underlying this illness. We sought evidence of such phenotypes using magnetic resonance spectroscopy based on previously described regional abnormalities in levels of the neuronal marker N-acetyl-aspartate (NAA) in the hippocampal area and dorsolateral prefrontal cortex of patients with schizophrenia.

METHODS

We studied 47 schizophrenics, 60 unaffected siblings, and 66 healthy control subjects with long echo time multislice proton magnetic resonance spectroscopic imaging, primarily measuring NAA, creatine plus phosphocreatine (CRE), and choline-containing compounds.

RESULTS

Both patients and their unaffected siblings had significant reductions in hippocampal area NAA/CRE as compared with control subjects. As exploratory analyses, estimates of heritability were performed. Although quantitative correlation of hippocampal NAA between patients and sibs was low (likely reflecting measurement noise), qualitatively defined "low hippocampal NAA/CRE phenotypes" yielded relative risk estimates (lambda s) of between 3.8 and 8.8, suggesting this characteristic is heritable.

CONCLUSIONS

Our finding adds to the evidence that hippocampal abnormalities are associated with schizophrenia and may represent a novel biological phenotype for genetic studies of schizophrenia.

Early self-experienced neuropsychological deficits and subsequent schizophrenic diseases: an 8-year average follow-up prospective study

The aim of the present study was to investigate the potential predictive value of early self-experienced neuropsychological deficits for the subsequent development of schizophrenia. A total of 96 patients with DSM-III-R diagnoses of personality disorders (formerly called 'neurotic disorders') who had been examined for the presence of such subjective experiences of deficits with standardized instruments were re-examined for the possible development of schizophrenic symptoms. After an average follow-up period of about 8 years, more than 50% of the patients had developed schizophrenia according to DSM-III-R criteria. In 77% of cases the outcome 'schizophrenia vs. no schizophrenia' was correctly predicted by the earlier presence or absence of self-experienced disturbances of thought, speech, memory, perception and action. These findings suggest that certain self-experienced neuropsychological deficits are able to indicate susceptibility to psychosis.