Syndromes of chronic schizophrenia and some clinical correlates

Executive Functions and Psychopathology Dimensions in Deficit and Non-Deficit Schizophrenia

This study: (a) compared executive functions between deficit (DS) and non-deficit schizophrenia (NDS) patients and healthy controls (HC), controlling premorbid IQ and level of education; (b) compared executive functions in DS and NDS patients, controlling premorbid IQ and psychopathological symptoms; and (c) estimated relationships between clinical factors, psychopathological symptoms, and executive functions using structural equation modelling. Participants were 29 DS patients, 44 NDS patients, and 39 HC. Executive functions were measured with the Mazes Subtest, Spatial Span Subtest, Letter Number Span Test, Color Trail Test, and Berg Card Sorting Test. Psychopathological symptoms were evaluated with the Positive and Negative Syndrome Scale, Brief Negative Symptom Scale, and Self-evaluation of Negative Symptoms. Compared to HC, both clinical groups performed poorer on cognitive flexibility, DS patients on verbal working memory, and NDS patients on planning. DS and NDS patients did not differ in executive functions, except planning, after controlling premorbid IQ and negative psychopathological symptoms. In DS patients, exacerbation had an effect on verbal working memory and cognitive planning; in NDS patients, positive symptoms had an effect on cognitive flexibility. Both DS and NDS patients presented deficits, affecting the former to a greater extent. Nonetheless, clinical variables appeared to significantly affect these deficits.

Rating scale for the assessment of communication disorders in schizophrenics

Taking up the Bleulerian view of a clinical description based on a pathogenic model, we propose a rating scale for the assessment of communication disorders in schizophrenic patients. The scale consists of clinical items that could be the direct expression of the three hypotheses of cognitive dysfunction which have been postulated to explain communication dysfunction in these patients. We assessed the frequency of the 16 items in the scale in a total of 80 subjects (43 schizophrenic subjects, ten manic subjects, 17 depressive subjects and ten normal control subjects). The results of this study showed that this item schedule was specific to schizophrenic patients and, in particular, could statistically significantly discriminate schizophrenic patients from psychotic patients with affective disorder. The methodological qualities of the scale were explored and proved accurate, except for the reliability which is too low for some items and the item-to-total correlation which is too low for one item of the scale.

Impairments in executive functioning in patients with remitted and non-remitted schizophrenia

OBJECTIVE

Although deficits in executive functioning are prominent in schizophrenia, some patients in remission have shown significantly higher levels of neurocognitive functioning than patients not in remission. However, no consensus on the relationship between neurocognitive functioning and the severity of symptoms has been reached. Additionally, previous studies have mainly examined the primary symptom domains of schizophrenia without considering the influence of anxiety symptoms, which are likely to influence neuropsychological performance. The aim of the present study was to compare the executive functioning of normal controls and with that of patients with schizophrenia in acute and remitted states. We further examined associations between impaired executive functioning in patients and anxiety levels.

METHODS

Using a battery of tests assessing executive functioning including subtests of the Cambridge Neuropsychological Automated Test Battery (CANTAB) and the short form of the Korean Wechsler Adult Intelligence Scale (K-WAIS), we assessed 54 patients with schizophrenia and 33 normal controls.

RESULTS

Our results showed that patients with non-remitted schizophrenia obtained significantly lower estimated IQ scores than did normal controls. They also exhibited longer reaction times on the Choice Reaction Time (CRT) test and the Stop Signal Test (SST) subtests of CANTAB and a greater number of total errors and errors that occurred before the extradimensional stage (i.e., pre-ED errors) on the Intradimensional/Extradimensional Shift (IED) subtest of CANTAB. Furthermore, those with schizophrenia in acute states showed significantly slower stop signal reaction times (SSRT) on the SST than did those with remitted schizophrenia and healthy controls. Finally, differences in the pre-ED errors and total adjusted errors on the IED became insignificant when scores on the Beck Anxiety Inventory (BAI) were entered as the covariate, whereas other significant differences remained when these scores were entered.

CONCLUSION

Differences in executive functioning exist between patients with schizophrenia and healthy controls; these differences can be largely attributed to the relatively poor performance of patients in an active state.

Combining dimensional and categorical representation of psychosis: the way forward for DSM-V and ICD-11?

BACKGROUND

There is good evidence that psychotic symptoms segregate into symptom dimensions. However, it is still unclear how these dimensions are associated with risk indicators and other clinical variables, and whether they have advantages over categorical diagnosis in clinical practice. We investigated symptom dimensions in a first-onset psychosis sample and examined their associations with risk indicators and clinical variables. We then examined the relationship of categorical diagnoses to the same variables.

METHOD

We recruited 536 patients as part of a population-based, incidence study of psychosis. Psychopathology was assessed using the Schedules for Clinical Assessment in Neuropsychiatry (SCAN). A principal axis factor analysis was performed on symptom scores. The relationship of dimension scores with risk indicators and with clinical variables was then examined employing regression analyses. Finally, regression models were compared to assess the contribution of dimensions versus diagnosis in explaining these variables.

RESULTS

Factor analysis gave rise to a five-factor solution of manic, reality distortion, negative, depressive and disorganization symptom dimensions. The scores of identified dimensions were differentially associated with specific variables. The manic dimension had the highest number of significant associations; strong correlations were observed with shorter duration of untreated psychosis, acute mode of onset and compulsory admission. Adding dimensional scores to diagnostic categories significantly increased the amount of variability explained in predicting these variables; the reverse was also true but to a lesser extent.

CONCLUSIONS

Categorical and dimensional representations of psychosis are complementary. Using both appears to be a promising strategy in conceptualising psychotic illnesses.

Is executive impairment associated with schizophrenic syndromes? A meta-analysis

BACKGROUND

A key neuropsychological proposal in schizophrenia is that negative and disorganization symptoms are associated with different patterns of impairment on executive tasks.

METHOD

Studies reporting correlations between positive, negative or disorganization symptoms and any type of executive test were meta-analysed. The influence of moderating factors was also examined, including age, treatment and stage of illness and whether symptoms were relapsing or persistent. The magnitudes of the correlations were compared with those for general intellectual impairment.

RESULTS

Pooled correlations between executive impairment and both negative symptoms and disorganization were significant in the small-to-moderate range. That for positive symptoms ('reality distortion'), however, was close to zero. The pattern of correlations among different executive tests differed significantly for negative symptoms and disorganization. Patients with stable clinical pictures showed significantly higher correlations with executive impairment than those with relapsing and remitting illnesses. Both negative symptoms and disorganization also correlated significantly with general intellectual function as indexed by current IQ.

CONCLUSIONS

Meta-analysis supports the view that negative symptoms and disorganization are associated with partially dissociable patterns of executive impairment. However, co-existent general intellectual impairment has been an important confounding factor in the studies to date.

Schizotypy and false memory

Using the Deese-Roediger-McDermott (DRM) paradigm the present study examined the relationship between schizotypy and recognition memory. Participants scoring in the upper and lower quartile ranges for schizotypy (Schizotypal Personality Questionnaire brief version; SPQ-B) and on each of the SPQ-B subscales (cognitive-perceptual, interpersonal and disorganized) were compared on true and false memory performance. Participants scoring in the lower quartile range on the cognitive-perceptual subscale recognised a higher proportion of both true and false memories than those scoring in the higher quartile range. Participants scoring in the upper quartile on the interpersonal factor recognised fewer true items than those in the lower quartile range. No differences were found for overall schizotypy or on the disorganized subscale.

Do symptom dimensions or categorical diagnoses best discriminate between known risk factors for psychosis?

OBJECTIVE

To describe symptom dimensions of psychosis using detailed psychopathological information from epidemiologically defined incident cases which include the full spectrum of functional psychosis across all age ranges. Then, assess the comparative usefulness of the dimensional and categorical representations of psychosis in discriminating between demographic and pre-morbid risk factors.

METHOD

A total of 464 incident cases of psychosis assessed with OPCRIT (Operational Checklist for Psychotic Symptoms) were included in an exploratory factor analysis. Using Regression analyses we modelled the associations of the dimensional and categorical representations of psychosis with antecedent validating variables and compared the subsequent models using the likelihood ratio test.

RESULTS

Factor analysis produced five-symptom dimensions, manic, disorganisation, depressive, delusional and auditory hallucinatory symptoms, explaining 58% of the total variance. Different dimensions were differentially associated with the pre-morbid risk factors. Neither the dimensional nor the categorical representations on their own were sufficient to explain associations with the antecedent validating variables.

CONCLUSION

Neither the dimensional or the diagnostic representation of psychosis was superior in discriminating between known risk factors, combining dimensional measures with categorical diagnoses will probably be more informative in determining the causes and correlates of psychosis.

Can patients at risk for persistent negative symptoms be identified during their first episode of psychosis?

Patients with schizophrenia who show persistent negative symptoms are an important subgroup, but they are difficult to identify early in the course of illness. The objective of this study was to examine characteristics that discriminate between first-episode psychosis (FEP) patients in whom primary negative symptoms did or did not persist after 1 year of treatment. Patients with a DSM-IV diagnosis of FEP whose primary negative symptoms did (N = 36) or did not (N = 35) persist at 1 year were contrasted on their baseline and 1-year characteristics. Results showed that patients with persistent primary negative symptoms (N = 36) had a significantly longer duration of untreated psychosis (p < .005), worse premorbid adjustment during early (p < .001) and late adolescence (p < .01), and a higher level of affective flattening (p < .01) at initial presentation compared with patients with transitory primary negative symptoms. The former group also showed significantly lower remission rates at 1 year (p < .001). Multiple regression analysis confirmed the independent contribution of duration of untreated psychosis, premorbid adjustment, and affective flattening at baseline to the patients' likelihood of developing persistent negative symptoms. It may therefore be possible to distinguish a subgroup of FEP patients whose primary negative symptoms are likely to persist on the basis of characteristics shown at initial presentation for treatment.

The factor structure for the Positive and Negative Syndrome Scale (PANSS) in recent-onset psychosis

The Positive and Negative Syndrome Scale (PANSS) is a widely used instrument for measuring severe psychopathology in adult patients with schizophrenia. Data, primarily on chronic patients, have been used to define factors for the PANSS. The present study examines the PANSS factor structure in a large sample of subjects with recent-onset schizophrenia, schizophreniform disorder and schizoaffective disorder who had been exposed to very limited antipsychotic medication. Equamax factor analysis was conducted on PANSS baseline assessments from a multicenter, 11 country drug trial that enrolled 535 patients. The forced five-factor solution essentially corresponds to the factors most frequently described previously, namely negative, positive, disorganized (or cognitive), excited and anxiety/depression. In the exploratory analysis, a seven-factor solution was obtained, with depression and anxiety symptoms separating and a motor component emerging. The results of this study partially support the use of a five-factor model for the PANSS, but suggest that scales for catatonia, depressive and anxiety syndromes should be included in future studies.

The cognitive and anatomo-functional basis of reality distortion in schizophrenia: a view from memory event-related potentials

This study investigated the neural and cognitive correlates of reality distortion in schizophrenia by using event-related potentials (ERPs) recorded in a recognition memory task for face. This task has been chosen because previous studies have shown that it provides distinct indices related to specific cognitive processes and to the functioning of specific brain regions. ERPs have been recorded in controls and schizophrenia patients separated into high scorers (RD+) and low-scorers (RD-) according to their Reality Distortion score (hallucination and delusion SAPS subscales). The results indicate that RD+ presents abnormalities on various cognitive processes. First, RD+ are deficient at interference inhibition and knowledge integration (reduced P2a and N400 effect). The similar impairments found in RD- suggest that they represent basic traits of the illness. Second, RD+ showed inappropriate stimulus categorization and contextual integration (larger N300 and fronto-central effect). Third, RD+ showed a late index (P600 effect) not different from controls, but larger than in RD-. This result is consistent with a qualitative, rather than quantitative, impairment of mnemonic binding processes (inappropriate binding) in RD+. Since each of the ERP abnormalities observed represents associated with distinct brain dysfunction, the results are further discussed in regard of the respective contribution of the parietal, frontal and hippocampal structures to reality distortion symptoms.

Negative symptoms in first episode non-affective psychosis

OBJECTIVE

To determine the prevalence of negative symptoms and to examine secondary sources of influence on negative symptoms and the role of specific negative symptoms in delay associated with seeking treatment in first episode non-affective psychosis.

METHOD

One hundred and ten patients who met Diagnostic Statistical Manual-IV (DSM-IV) criteria for a first episode of schizophrenia spectrum psychoses were rated for assessment of negative, positive, depressive and extrapyramidal symptoms, the premorbid adjustment scale and assessment of demographic and clinical characteristics including duration of untreated psychosis (DUP).

RESULTS

Alogia/flat affect and avolition/anhedonia were strongly influenced by parkinsonian and depressive symptoms, respectively. A substantial proportion (26.8%) of patients showed at a least moderate level of negative symptoms not confounded by depression and Parkinsonism. DUP was related only to avolition/anhedonia while flat affect/alogia was related to male gender, diagnosis of schizophrenia, age of onset and the length of the prodrome.

CONCLUSION

Negative symptoms that are independent of the influence of positive symptoms, depression and extra pyramidal symptoms (EPS) are present in a substantial proportion of first episode psychosis patients and delay in seeking treatment is associated mainly with avolition and anhedonia.

Working memory correlates of three symptom clusters in schizophrenia

This study was designed to examine whether discrete working memory deficits underlie positive, negative and disorganised symptoms of schizophrenia. Symptom dimension ratings were assigned to 52 outpatients with schizophrenia (ICD-10 criteria), using items drawn from the Positive and Negative Syndrome Scale (PANSS). Linear regression and correlational analyses were conducted to examine whether symptom dimension scores were related to performance on several tests of working memory function. Severity of negative symptoms correlated with reduced production of words during a verbal fluency task, impaired ability to hold letter and number sequences on-line and manipulate them simultaneously, reduced performance during a dual task, and compromised visuospatial working memory under distraction-free conditions. Severity of disorganisation symptoms correlated with impaired visuospatial working memory under conditions of distraction, failure of inhibition during a verbal fluency task, perseverative responding on a test of set-shifting ability, and impaired ability to judge the veracity of simple declarative statements. Severity of positive symptoms was uncorrelated with performance on any of the measures examined. The present study provides evidence that the positive, negative and disorganised symptom dimensions of the PANSS constitute independent clusters, associated with unique patterns of working memory impairment.

Neuropsychological correlates of schizophrenic syndromes in patients treated with atypical neuroleptics

There is widespread evidence that schizophrenic symptomatology is best represented by three syndromes (positive, negative, disorganized). Both the disorganized and negative syndrome have been found to correlate with several neurocognitive dysfunctions. However, previous studies investigated samples predominantly treated with typical neuroleptics, which frequently induce parkinsonian symptoms that are hard to disentangle from primary negative symptoms and may have inflated correlations with neurocognition. A newly developed psychopathological instrument called the Positive and Negative and Disorganized Symptoms Scale (PANADSS) was evaluated in 60 schizophrenic patients. Forty-seven participants treated with atypical neuroleptics performed several neurocognitive tasks.A three-factor solution of schizophrenic symptomatology emerged. Negative symptomatology was associated with diminished creative verbal fluency and digit span backward, whereas disorganization was significantly correlated with impaired Stroop, WCST and Trail-Making Test B performance.Data suggest that disorganization is associated with tasks that demand executive functioning. Previous findings reporting correlations between negative symptomatology and neurocognition may have been confounded by the adverse consequences of typical neuroleptics.

Dementia as a complication of schizophrenia

OBJECTIVES

Cognitive impairment is known to occur in schizophrenia, and may be marked in institutionalised patients. The aim of this study was to determine whether it ever warrants an additional diagnosis of dementia.

METHODS

A population of chronic schizophrenic patients who were aged 65 or younger and showed no organic risk factors for dementia were screened for presence of disorientation. Any showing this underwent neuropsychological testing, physical investigations, and structural and functional neuroimaging. Information about day to day cognitive function was also obtained from carers.

RESULTS

Eight patients aged 28 to 64 were identified who showed disorientation; in all cases this was accompanied by general intellectual impairment and objective evidence of a dementia syndrome. The patients' schizophrenic symptoms were unexceptional and did not seem sufficient to account for their cognitive impairment. Neuropsychological testing disclosed relative sparing of visual and visuospatial function and language syntax, but pervasive deficits in memory and executive function. Brain CT demonstrated only minor abnormalities but most of the patients showed frontal or temporal hypoperfusion on SPECT.

CONCLUSIONS

Dementia in schizophrenia seems to be a real entity with a neuropsychological signature similar to that of frontotemporal dementia. Functional but not structural imaging abnormalities may also be characteristic.

The factor structure for positive and negative symptoms in South African Xhosa patients with schizophrenia

Most studies investigating the symptom dimensions of schizophrenia utilising the Scale for the Assessment of Negative Symptoms (SANS) and the Scale for the Assessment of Positive Symptoms (SAPS) favour a three factor model. This study sought to investigate the factor structure of both the global and individual items of the SANS and SAPS in a large sample of South African Xhosa patients with schizophrenia. A total of 422 subjects participated. Both principal components and factor analytical procedures were applied. For the global items, a two-factor solution representing positive and negative symptoms accounted for 59.9% of the variance. Alternatively, the three-dimensional model of negative, psychotic and disorganisation factors was supported by a five-factor solution if the more heterogeneous items of attention and alogia were ignored. Analysis of the individual items yielded a five-factor solution with the negative symptoms splitting into diminished expression and disordered relating, and the positive symptoms separating into factors for psychosis, thought disorder and bizarre behaviour. Our findings are very similar to those from other parts of the world, providing evidence that the factor structure for the symptoms of schizophrenia is relatively resistant to cultural influences. This is particularly true for negative symptoms.

Familiality of symptom dimensions in schizophrenia

The division of schizophrenic symptoms into three core dimensions - psychomotor poverty, reality distortion, and disorganisation - is well established. When factor analytic studies have included affective symptoms they have identified two additional dimensions - manic and depressive. Whether these five dimensions represent underlying psychopathology of a genetic or environmental aetiology remains unclear. The aims of this study were to perform factor analysis of symptoms in a group of familial schizophrenic patients and to investigate the familiality of the symptom dimensions identified, and their relationship to clinical characteristics. Symptoms were recorded, using the Operational Criteria Checklist for Psychotic Illness, for 155 Caucasian subjects with an RDC diagnosis of schizophrenia, schizoaffective disorder, or psychosis of unknown origin, from 61 families multiply affected with schizophrenia. Factor analysis indicated five symptom dimensions: depressive, manic, reality distortion, disorganisation, and psychomotor poverty. The psychomotor poverty, disorganisation, and manic dimensions were shown to be familial. Psychomotor poverty, disorganisation, and reality distortion were all associated with deterioration from premorbid functioning and chronic course of the disorder. In addition, psychomotor poverty was significantly related to poor premorbid functioning, as well as to single marital status and unemployment at onset. Disorganisation was significantly related to single marital status and unemployment at onset. The familiality of the psychomotor poverty, disorganisation, and manic dimensions supports their use in the delineation of homogeneous subsets for genetic studies.

An analysis of the specificity and the syndromal correlates of verbal memory impairments in schizophrenia

It was investigated whether schizophrenic and depressive patients show a distinguishable mnestic profile. A further aim was to explore the psychopathological correlates of memory malperfomance in schizophrenic patients. For the present study, schizophrenic, depressive and healthy samples (n=25 each) were compared regarding their performance in the Rey Auditory Verbal Learning Test. Subjects' sociodemographic background variables were comparable except for age (entered as a covariate). Depressive and schizophrenic patients performed significantly worse than healthy controls regarding both short-term and long-term free recall as well as recognition. No differences occurred for two parameters reflecting proneness to interference. Negative schizophrenic symptomatology was strongly correlated with memory dysfunction before and after controlling for distractibility. The study supports previous research suggesting that memory impairments in schizophrenia are not an epiphenomenon of deficits in verbal fluency or an attentional impairment. The major deficit in both schizophrenic and depressive patients is inferred to be the capability to learn.

Impairment in test performance and symptom dimensions of schizophrenia

Schizophrenic patients were rated on three syndromal dimensions derived from positive and negative symptom ratings. Scores on each dimension were compared to performance on neuropsychological tests before and after coaching instructions. Patients evidenced significant improvement in performance on all measures readministered immediately after instruction. Disorganization symptoms were correlated with lower levels of performance on all pre-coaching, trial 1 tests. Disorganization symptoms were also associated with lower levels of trial 2 post-coaching performance, independent of pre-coaching scores. These results suggest that, within a population of schizophrenic patients, symptoms of disorganization are associated with relatively greater impairments in performance on neuropsychological tests and with impaired ability to improve test performance following coaching instructions. The three symptom dimensions show promise for reducing heterogeneity within samples of schizophrenic patients.

Defining the phenotype of schizophrenia: cognitive dysmetria and its neural mechanisms

All research on schizophrenia depends on selecting the correct phenotype to define the sample to be studied. Definition of the phenotype is complicated by the fact that there are no objective markers for the disorder. Further, the symptoms are diverse, leading some to propose that the disorder is heterogeneous and not a single disorder or syndrome. This article explores an alternative possibility. It proposes that schizophrenia may be a single disorder linked by a common pathophysiology (a neurodevelopmental mechanism), which leads to a misconnection syndrome of neural circuitry. Evidence for disruption in a specific circuit is explored: the cortical-thalamic-cerebellar-cortical circuit (CCTCC). It is suggested that a disruption in this circuit leads to an impairment in synchrony, or the smooth coordination of mental processes. When synchrony is impaired, the patient suffers from a cognitive dysmetria, and the impairment in this basic cognitive process defines the phenotype of schizophrenia and produces its diversity of symptoms.

Comparison of set-shifting ability in patients with chronic schizophrenia and frontal lobe damage

Neuropsychological studies of patients with schizophrenia have consistently identified deficits on tests sensitive to frontal lobe function. One paradigm that has been widely used is that of attentional set-shifting using the Wisconsin Card Sorting Test (WCST). In the present study, patients with chronic schizophrenia and with frontal lobe lesions were assessed on a computerised set-shifting task that provides a componential analysis of the WCST by distinguishing between intra-dimensional and extra-dimensional set-shifting. Out of 51 patients with schizophrenia, those with high IQ (n =24) were compared with patients with lesions in prefrontal cortex (n = 22) and with normal control subjects (n= 18). These three groups were well matched for age, sex and National Adult Reading Test (NART) IQ. The schizophrenic group showed a significantly higher rate of attrition at the intra-dimensional shift stage of learning compared with the other two groups. At the extra-dimensional shift stage, both the schizophrenic and frontal lesioned groups showed greater attrition than controls. Further, patients with schizophrenia who were able to learn the intradimensional reversal stage required more trials and made significantly more errors at that stage than the other two groups. In comparison with high IQ patients with schizophrenia, those with low IQ performed at a lower level but showed a qualitatively similar pattern of performance, providing further evidence that the set-shifting deficits were not simply explained by any global intellectual decline. Patients with schizophrenia who dropped out at the extradimensional shift stage had higher negative symptom scores compared with patients dropping out at previous learning stages, while patients failing at the intra-dimensional shift stage had lower scores for bradyphrenia (slowness of thought). The results suggest that patients with chronic schizophrenia fail to 'learn set' and are impaired at both set-shifting and concept formation. The relevance of these findings to understanding the nature of prefrontal cortical deficits in chronic schizophrenia is discussed. The implication of these findings to the rehabilitation of these patients is considered.

The structure of schizophrenic symptoms: a meta-analytic confirmatory factor analysis

To quantitatively review all presently available evidence about the interrelations between positive and negative schizophrenic symptoms, we created an aggregate matrix of the intercorrelations among schizophrenic symptoms by combining data from 28 independent samples using meta-analytic procedures (net bivariate dfs ranging from 683 to 1657). Using confirmatory factor analyses, we then statistically compared four theoretically derived models of the structure of schizophrenic symptoms. Although a three-factor model (Liddle, 1987) best fit the data, results suggest that either more factors or different symptoms are required to account well for the latent structure underlying schizophrenic symptomatology. The nature of such augmented approaches, the opportunities and constraints inherent to multifactorial models, and the limitations of current instruments are discussed.

Neuropsychological deficits associated with schizophrenic syndromes

A battery of computerised tests and the classical Stroop test were administered to a group of 56 patients with DSM-III-R schizophrenia and 17 controls to explore the nature of the mental processes associated with the psychomotor poverty and disorganisation syndromes. In patients with persistent illness, psychomotor poverty was associated with slower responses in a two-choice guessing task in which the appropriate response was not dictated by the circumstances. This association was not observed in patients with remitting illness, providing neuropsychological support to the distinction between 'negative' and 'deficit' symptoms in schizophrenia. Disorganisation syndrome was associated with impaired performance in the classical Stroop test, as shown in previous studies, but not with impairment in a task which required suppression of processing of irrelevant aspects of a stimulus, nor with impairment in a task which required the suppressing of a primed but irrelevant non-verbal response. This suggests that the disorganisation syndrome might be associated with a specific difficulty in suppressing irrelevant verbal responses.

Schizophrenic syndromes and clozapine response in treatment-resistant schizophrenia

Relationships between symptom profile and clozapine response were studied. Symptom scores on the Scale for the Assessment of Positive Symptoms and the Scale for the Assessment of Negative Symptoms were subjected to principal component analysis (PCA) in a group of 66 treatment-resistant schizophrenic patients, 49 of whom were treated with clozapine. Factor scores were compared among responders, non-responders and partial responders. The PCA yielded a four-factor solution, with positive symptoms, negative symptoms, cognitive disorganization and behavioral disorganization components. Cognitive and behavioral disorganization syndrome scores showed significant differences across groups. Cognitive disorganization was higher in non-responders, while behavioral disorganization was higher in partial responders. The results support the possibility of using clinical profiles to predict therapeutic response to clozapine.

Subsyndromes of chronic schizophrenia: a phenomenological study

Statistical grouping of clinical symptoms and signs is one method of classifying schizophrenia. This study attempted to find factors of symptoms generated through clinical ratings on three scales, namely the Scale for the Assessment of Positive Symptoms (SAPS), the Scale for the Assessment of Negative Symptoms (SANS) and the Comprehensive Psychopathological Rating Scale (CPRS) in a sample of 80 stable chronic schizophrenics diagnosed by DSM-III-R. It was found that the positive-negative dichotomy could not be replicated. Inappropriate affect was found to be a clear misfit in the cluster of negative symptoms. Inclusion of CPRS led to the generation of a factor loading high on depressive and asthenic items, and this could be clearly distinguished from the factor of negative symptoms. This factor had not hitherto been identified.

Factor-derived subsyndromes of schizophrenia and familial morbid risks

Factor analysis was performed on OPCRIT checklist ratings from 66 patients with RDC schizophrenia. Eight substantive factors were found, characterised respectively by: positive formal thought disorder; first rank delusions; first rank hallucinations; inappropriate affect/bizarre behaviour; negative symptoms; grandiose/bizarre delusions; delusions of influence/persecution; and other hallucinations. A history of schizophrenia and other non-affective psychoses was ascertained in the probands' first-degree relatives using a family history approach. Illness in relatives was best predicted by probands' scores on subsyndromes derived from the inappropriate affect/bizarre behaviour and positive formal thought disorder factors.

Neuropsychological correlates of syndromes in schizophrenia

BACKGROUND

On the basis of Liddle's three-syndrome model of schizophrenia, it was predicted that: (1) symptoms of psychomotor poverty would be particularly correlated with impaired performance on neuropsychological tests likely to reflect functioning of the dorsolateral prefrontal cortex; (2) disorganisation would be particularly correlated with impaired performance on tests sensitive to medio-basal prefrontal functioning; and (3) reality distortion would be particularly correlated with measures sensitive to temporal lobe functioning.

METHOD

The above hypotheses were tested on 87 subjects with a confirmed diagnosis of schizophrenia. Patients' symptoms were scored for each of the three syndromes. Patients completed six neuropsychological tests designed to measure impairment in specific areas of the brain.

RESULTS

There was no support for the first two hypotheses. There was, however, evidence of a specific relationship between reality distortion and neuropsychological performance usually considered to be related to left temporal lobe functioning.

CONCLUSIONS

Although not directly supporting the first two hypotheses; the results are, in general, consistent with there being different cortical-subcortical circuits associated with each of psychomotor poverty and disorganisation. Temporal lobe functioning appears to have particular significance for the reality distortion syndrome.

Factor analysis of schizophrenic symptoms using the OPCRIT checklist

Factor analysis was performed on OPCRIT checklist psychotic symptoms rated on 102 patients with DSM-III-R schizophrenia. An initial three-factor solution produced positive, negative, and disorganisation factors. However, application of the scree test suggested five substantive factors, with the positive factor dividing into three factors characterised, respectively, by paranoid symptoms, first rank delusions and first rank hallucinations.

Cerebral metabolic activity correlates of subsyndromes in chronic schizophrenia

Seventy-nine patients with schizophrenia and 47 healthy controls received positron-emission tomography (PET) with 18F-2-deoxyglucose uptake while executing the Continuous Performance Test (CPT). Patients had been off all psychoactive medication for at least four weeks. Patients' symptoms were assessed with the Brief Psychiatric Rating Scale and factor scale scores were obtained. These scores were used in cluster analysis to identify patients with predominantly delusional, negative, disorganized, and remitted symptoms. To address the interconnective nature of cerebral functioning, regions of interest were defined on the basis of the results of a factor analysis of metabolic rate in selected brain regions. This procedure identified six cortical and eight subcortical region of interest factors. Metabolic rate factor scale scores were compared between the patients' clusters and the healthy controls. The delusional cluster showed a significantly reduced hippocampal activity, while the negative symptoms cluster presented with a prominent hypofrontality and significantly increased left temporal cortex values. Concurrently, both clusters were associated with a decreased activity on the factor 'anterior cingulum and medial frontal gyrus'. The disorganized cluster was characterized by a significant overactivity in the parietal cortex and motor strip and a decreased activity in the corpus callosum. The subsyndromes of chronic schizophrenia are therefore characterized by deviant patterns of cerebral activity rather than deficits in a single location.

A factor analytic study of symptoms in acute schizophrenia

The three-syndrome model of schizophrenic phenomenology has been well established in chronic illness. We report an attempt to replicate this concept in a sample of acutely unwell schizophrenic patients. Factor analysis was performed using PSE data collected within a week of admission from 114 patients who met DSMIII(R) diagnostic criteria for schizophrenia. Four main factors accounted for 58% of the variance. The first two factors closely resembled Liddle's disorganisation and psychomotor poverty syndromes. Hallucinations and delusions loaded separately under the third and fourth factors. To examine the validity of these four syndromes, the relationships between factor scores and other clinical data were examined. The disorganisation syndrome was associated with a history of multiple past admissions and a longer lifetime duration of in-patient treatment.

Psychopathological syndromes in the functional psychoses: associations with course and outcome

The aim of this study was to identify underlying dimensions of psychopathology in a cohort of patients with functional psychosis of recent onset, and to examine their prognostic value. Factor analysis of the psychopathological features of 166 consecutively admitted patients with functional psychosis of recent onset revealed seven psychopathological dimensions, which explained 63% of the variance. Five of these seven syndromes bore differential associations with subsequent treatment and illness course, independent of: (i) associations with DSM-III-R diagnosis; (ii) associations with other prognostic factors; and (iii) associations with the baseline values of outcome variables. The most striking associations were shown for an early and insidious onset syndrome with affective flattening, which predicted a more disabled course of illness on three of four outcome dimensions, and which was more common in males and unmarried individuals. A second syndrome, characterized by bizarre behaviour, inappropriate affect, catatonia, and poor rapport showed similar, slightly less striking, associations with illness course, as well as with poor pre-morbid social functioning. A third syndrome, characterized by positive psychotic symptoms was to a lesser degree associated with poorer outcome, whereas a fourth syndrome distinguished by manic symptomatology predicted a more benign illness course. A fifth syndrome identified by lack of insight predicted more time in hospital and admission under a section of the Mental Health Act during the follow-up period. A further finding was that dimensional representations of psychopathological features were considerably more useful than categorical representations (DSM-III-R and ICD-10) as predictors of illness course and treatment decisions.

Cognitive and psychophysiological correlates of positive, negative, and disorganized symptoms in the schizophrenia spectrum

This study examined the cross-sectional and prospective relationships between cognitive and psychophysiological variables and positive, negative, and disorganized symptoms in 40 outpatients with diagnoses of schizophrenia or schizoaffective disorder. The results indicated that disorganized symptoms were related to deficits in auditory and visuomotor attentional processing, increased skin conductance orienting response, and lower stress reactivity. Negative symptoms were related to reduced resting heart rate, increased stress reactivity, and deficits in visuomotor processing. Prospective findings indicated that both the cognitive and heart-rate variables might be trait-related aspects of the negative symptoms, while the skin conductance, but not the cognitive, variables might be trait-related aspects of the disorganized symptoms. Positive symptoms were not related to any of the cognitive or psychophysiological variables.

Three syndromes in schizophrenia: validity in young patients with recent onset of illness

The heterogeneity of schizophrenia constitutes an impediment in the identification of reliable biological markers of the illness and aetiological factors. The two syndrome concept of the illness has proved a powerful stimulus in this endeavour. There is however evidence now to regard this construct as inadequate and in need of refinement. Using a sample of young patients with early onset of illness who fulfilled the Research Diagnostic Criteria for schizophrenia, we have shown that three rather than two dimensions better describe the pathology of the illness. The results of factor analysis showed these syndromes, termed disorganization, positive, and negative syndromes, to account for 65% of the total variance of the psychopathology of the disorder. The negative syndrome was associated with disturbed pre-morbid functioning while the disorganization syndrome bore significant association with early onset of illness, poorer socio-educational attainment, and impairment on neuropsychological tests, especially those designed to evaluate frontal lobe functioning. The positive syndrome was not associated with any of the assessed variables. These results provide strong support for the validity of the three-syndrome construct even among a sample of non-institutionalized patients.

Inner connections within domain of dementia praecox: role of supervisory mental processes in schizophrenia

Kraepelin's conclusion that there were underlying common features justifying the amalgamation of catatonia, hebephrenia and paranoia hallucinatoria to form a single illness is confirmed by factor analytic studies delineating the various dimensions of schizophrenic psychopathology. Neuropsychological studies reveal that the three cardinal dimensions reflect disorder of the supervisory mental processes responsible for initiation, selection and monitoring of self-generated mental activity. Brain-imaging studies indicate that the underlying neuropathology entails disordered functional connectivity within the neural networks in multimodal association cortex that are the substrate of the supervisory mental processes, consistent with Kraepelin's own speculation about the essential nature of the condition.

An empirical analysis of latent structures underlying schizophrenic symptoms: a four-syndrome model

Various models of schizophrenia have postulated two syndromes (i.e., positive and negative), although other exploratory factor analyses have suggested a disorganization syndrome. We conducted a confirmatory factor analysis (CFA) on Schedule for the Assessment of Positive Symptoms (SAPS) and Schedule for the Assessment of Negative Symptoms (SANS) items and subscales to assess the latent structure of symptoms reflecting underlying pathological processes. The sample included 253 DSM-IIIR schizophrenic inpatients. Fourteen different models with one, two, three, or four syndromes were compared using CFA for "goodness of fit." The three-syndrome models displayed better fitness than any of the one- or two-syndrome models. All of the three-syndrome models shared the positive and negative dimensions; the third dimension in these three-syndrome models was either the disorganization or Strauss' relational dimensions. In the reported data, a four-syndrome model, including positive, disorganization, negative, and relational dimensions, showed excellent fitness. Despite its limitations, this study suggests the need to explore the validity of a four-syndrome model. The positive-negative model fits poorly with the data.

Positive and negative symptoms of schizophrenia: past, present, and future

The "group of schizophrenias," normally referred to with a single nominative, is phenomenologically heterogeneous. Its symptoms represent multiple psychological domains, including perception, inferential thinking, language, attention, social interaction, emotion expression, and volition. Studies of psychopathology have simplified this complex array in several ways; one has been a subdivision into positive and negative symptoms. Reports by our group and others suggest that the symptoms of schizophrenia fall into three natural dimensions: positive symptoms subdivided into psychotic and disorganized dimensions, while a third negative dimension also emerges. Since these dimensions have impressive consistency across studies, future work must examine their relationship to clinically relevant concepts such as prognosis or etiology and examine four different aspects: longitudinal course, neural mechanisms, relationship to treatment, and interrelationships in other pathological conditions.

An analysis of the clinical features of familial schizophrenia

Clinical features of familial schizophrenia were examined in 169 siblings from 80 families. Factor analysis of symptoms produced a negative symptom factor (affective flattening and negative thought disorder), a disorganization factor (inappropriate affect and positive thought disorder) and a reality distortion factor (delusions and hallucinations). The negative symptom factor correlated positively with duration of illness and poor outcome. The disorganization factor correlated positively with poor outcome and early age at onset. The only clear correlation between these factors and affective symptoms was a negative one between the negative symptom factor and mania. There were no significant gender differences in age at onset, factor scores or outcome. The implication of these findings in relation to recent research in the areas of psychopathology and epidemiology are discussed.

Clinical heterogeneity in schizophrenia and the pattern of psychopathology in relatives: results from an epidemiologically based family study

Individuals with schizophrenia vary widely in their symptoms, course of illness and outcome. Family background is the strongest known risk factor for schizophrenia. We know little of the relationship between clinical variability in this disorder and the level of familial vulnerability to schizophrenia and other major mental disorders. Therefore, in schizophrenic probands meeting DSM-III-R criteria (n = 126) from the epidemiologically based Roscommon Family Study, we systematically assessed 9 major symptoms, course, global outcome, Schedule for Negative Symptoms and the Levels of Functioning Scale. These clinical characteristics were related t the risk of mental disorders in first-degree relatives assessed by personal interview or hospital records (n = 354) utilizing both the "familial/sporadic" and the Cox proportional hazard models. Using either statistical method, no consistent and significant relationship was found between any of our measures of symptoms, course or outcome and the risk for schizophrenia or schizophrenia spectrum disorders in relatives. Similarly, no relationship was found between these clinical measures and the risk for affective illness, alcoholism or anxiety disorders. Our results are not consistent with previously articulated hypotheses that negative symptoms or poor outcome in schizophrenia reflect a high familial liability to illness. While familial factors contribute substantially to an individual's vulnerability to schizophrenia, our results suggest that once an individual is affected, these same factors do not strongly influence either the kinds of symptoms displayed or the course and outcome of the illness.

Three clinical syndromes of schizophrenia in untreated subjects: relation to brain glucose activity measured by positron emission tomography (PET)

A number of studies of chronically ill, medicated patients have found that the clinical symptoms of schizophrenia segregate into three syndromes which can be labelled poverty, disorganization, and reality distortion. It has been previously found that each of these syndromes is associated with a specific pattern of perfusion (rCBF) in paralimbic and association cortex and in related subcortical nuclei. We replicated the symptom factors in 20 untreated subjects. Utilizing positron emission tomography with 18-F-fluorodeoxyglucose as a tracer for glucose metabolism, we reconstructed a map of the entire cortical activity from 16 to 20 tomographic slices. Each of the three syndromes was associated with a different pattern of regional glucose metabolism. Findings in common with previous studies were an association of poverty with left cortical metabolic activity in prefrontal and superior parietal areas, reality distortion with left temporal activity, and disorganization with left inferior parietal lobule. This is the first report of an association between regional metabolic activity and clinical syndromes in untreated patients, strengthening previous models of distributed neural networks in this disorder.

The evaluation of the severity of illness, affective blunting and neuroleptic treatment outcome in schizophrenic subgroups

In 61 schizophrenic patients divided into subgroups according to DSM III-R, positive/negative symptoms and Leonhard's classification of systematic and non-systematic schizophrenia, the severity of illness (BPRS) and affective blunting (MARS and RSEB scales) were measured before and after neuroleptic therapy. The evaluation of affective blunting with the use of RSEB revealed more significant differences within schizophrenic subgroups than with the use of MARS. The severity of illness did not differentiate the subgroups studied. The affective blunting was more severe in patients with systematic than with non-systematic schizophrenia as well as in mixed and negative than in positive schizophrenia. The severity of illness correlated however with the severity of affective blunting. Clinical improvement after neuroleptic treatment was more favorable in patients with positive schizophrenia. The diminution of affective blunting after neuroleptic therapy varied among the subgroups.