Schizophrenia: comparison of 13 diagnostic systems in a cross-sectional study 1

Principal-component analyses of PANSS and SANS-SAPS in schizophrenia: their stability in an acute phase

Whether studies agree or disagree on the positive-negative dichotomy in schizophrenia, the relevance of a third component, disorganization, remains a point of debate. Disorganization, as expressed by the scale for the assessment of negative symptoms and positive symptoms (SANS-SAPS) and the positive and negative syndrome scale (PANSS) principal-component analyses, could be considered as permanent and determinant a dimension as the positive and negative components. The aim of this study therefore was to determine whether this disorganization, with the negative and positive components, is stable and has the same composition in the acute and postacute phases of illness. This study was carried out in 57 patients, broadly defined by at least one of four diagnostic criteria (American Psychiatric Association, Langfeldt, Carpenter and Schneider), established with a computerized checklist, and evaluated with SANS-SAPS and PANSS. Principal component analyses (PCA) of these scales were performed at admission and discharge from hospital.

The PCA of SANS-SAPS displayed a 3-factor solution, regardless of the phase of illness (acute or postacute), showing that the negative, positive and disorganization components were stable. The PCA of PANSS yielded negative and positive components perfectly stable over time and a disorganization component whose composition varied between admission and discharge. At admission, this component included the conceptual disorganization item negatively correlated with one of depression. At discharge, this disorganization component included two additional items, autistic preoccupation and mannerisms and one depression component appeared. The instability of the PCA of PANSS could express the role played by the phase of illness; in an acute phase, this disorganization component was constituted by more “positive” items such as grandiosity, unusual thought content and active social avoidance whereas in the postacute phase, it included items that reflected more the chronicity of the illness, such as mannerisms and autistic preoccupation. Moreover, the depressive item appeared, in the postacute phase, in a specific depressive component. This result could be due to the fact that depressive symptoms cannot be expressed when positive symptoms are very severe, which explains why no depressive components were shown during the acute phase.

Stability of positive and negative symptoms in schizophrenic patients: a 3-year follow-up study

The course of negative and positive symptoms was studied in neuroleptic-treated patients over a 3-year period, in consideration also of the initial phase of illness (post-acute or chronic). This study was carried out in a broadly defined schizophrenic sample, in order not to give preference to one diagnostic subgroup over another. Forty-six patients were evaluated every year for 3 years, 23 in the post-acute group and 23 in the chronic group. Aggravations of the Clinical Global Impression (CGI) and of the SANS total score were observed, regardless of the group (chronic or post-acute). This global aggravation confirmed Kraepelin's concept of dementia praecox; moreover, this aggravation was not due to an increase in the number of patients relapsing, or to an aggravation of akinesia. Three types of negative and positive symptom courses were observed: i) the mean sub-scores of positive symptoms, such as hallucinations, delusions, positive formal thought disorders, and of negative symptoms such as flattening affect, avolition/apathy and attentional impairment, did not vary significantly over time in either group; ii) the mean sub-scores of bizarre behavior and alogia fluctuated over time (p < 0.05) and only poverty of speech was perfectly stable among the items constituting alogia; iii) the mean subscores of anhedonia/asociality worsened significantly over time irrespective of the groups (p < 0.05), and among the items constituting anhedonia, recreational interest-activities and intimacy-closeness abilities worsened (p < 0.05 and p < 0.01, respectively). This aggravation was neither due to an increase in neuroleptic doses nor to the duration and chronicity of illness. However, negative symptoms, except anhedonia, can be reversible in some patients. The very strong stability of anhedonia, whatever the group, emphasize the importance of taking anhedonia into account in future diagnostic classifications.

First rank symptoms for schizophrenia

BACKGROUND

Early and accurate diagnosis and treatment of schizophrenia may have long-term advantages for the patient; the longer psychosis goes untreated the more severe the repercussions for relapse and recovery. If the correct diagnosis is not schizophrenia, but another psychotic disorder with some symptoms similar to schizophrenia, appropriate treatment might be delayed, with possible severe repercussions for the person involved and their family. There is widespread uncertainty about the diagnostic accuracy of First Rank Symptoms (FRS); we examined whether they are a useful diagnostic tool to differentiate schizophrenia from other psychotic disorders.

OBJECTIVES

To determine the diagnostic accuracy of one or multiple FRS for diagnosing schizophrenia, verified by clinical history and examination by a qualified professional (e.g. psychiatrists, nurses, social workers), with or without the use of operational criteria and checklists, in people thought to have non-organic psychotic symptoms.

SEARCH METHODS

We conducted searches in MEDLINE, EMBASE, and PsycInfo using OvidSP in April, June, July 2011 and December 2012. We also searched MEDION in December 2013.

SELECTION CRITERIA

We selected studies that consecutively enrolled or randomly selected adults and adolescents with symptoms of psychosis, and assessed the diagnostic accuracy of FRS for schizophrenia compared to history and clinical examination performed by a qualified professional, which may or may not involve the use of symptom checklists or based on operational criteria such as ICD and DSM.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened all references for inclusion. Risk of bias in included studies were assessed using the QUADAS-2 instrument. We recorded the number of true positives (TP), true negatives (TN), false positives (FP), and false negatives (FN) for constructing a 2 x 2 table for each study or derived 2 x 2 data from reported summary statistics such as sensitivity, specificity, and/or likelihood ratios.

MAIN RESULTS

We included 21 studies with a total of 6253 participants (5515 were included in the analysis). Studies were conducted from 1974 to 2011, with 80% of the studies conducted in the 1970's, 1980's or 1990's. Most studies did not report study methods sufficiently and many had high applicability concerns. In 20 studies, FRS differentiated schizophrenia from all other diagnoses with a sensitivity of 57% (50.4% to 63.3%), and a specificity of 81.4% (74% to 87.1%) In seven studies, FRS differentiated schizophrenia from non-psychotic mental health disorders with a sensitivity of 61.8% (51.7% to 71%) and a specificity of 94.1% (88% to 97.2%). In sixteen studies, FRS differentiated schizophrenia from other types of psychosis with a sensitivity of 58% (50.3% to 65.3%) and a specificity of 74.7% (65.2% to 82.3%).

AUTHORS' CONCLUSIONS

The synthesis of old studies of limited quality in this review indicates that FRS correctly identifies people with schizophrenia 75% to 95% of the time. The use of FRS to diagnose schizophrenia in triage will incorrectly diagnose around five to 19 people in every 100 who have FRS as having schizophrenia and specialists will not agree with this diagnosis. These people will still merit specialist assessment and help due to the severity of disturbance in their behaviour and mental state. Again, with a sensitivity of FRS of 60%, reliance on FRS to diagnose schizophrenia in triage will not correctly diagnose around 40% of people that specialists will consider to have schizophrenia. Some of these people may experience a delay in getting appropriate treatment. Others, whom specialists will consider to have schizophrenia, could be prematurely discharged from care, if triage relies on the presence of FRS to diagnose schizophrenia. Empathetic, considerate use of FRS as a diagnostic aid - with known limitations - should avoid a good proportion of these errors.We hope that newer tests - to be included in future Cochrane reviews - will show better results. However, symptoms of first rank can still be helpful where newer tests are not available - a situation which applies to the initial screening of most people with suspected schizophrenia. FRS remain a simple, quick and useful clinical indicator for an illness of enormous clinical variability.

Association of DNA polymorphism in the first intron of the tyrosine hydroxylase gene with disturbances of the catecholaminergic system in schizophrenia

We examined whether there are clinical or biological differences in chronic schizophrenic patients sharing a rare variant allele (a perfect ten tetranucleotide repeats allele of the human TH01 microsatellite) in the tyrosine hydroxylase (TH) gene. For that purpose, clinical parameters (PANSS subscores) and plasma measurements (homovanillic acid and 3-methoxy-4-hydroxy-phenylglycol (MHPG)) were analyzed in five schizophrenic patients sharing the rare allele and 19 schizophrenic patients who did not possess this allele. The mean concentration of plasma HVA and plasma MHPG were significantly lower in the group of schizophrenic patients sharing the rare allele. No other group differences were observed between both groups. These results suggest that this TH gene polymorphism may be associated with disturbances of the catecholaminergic pathway.

Relationship between depressive and positive symptoms in schizophrenia

The aim of this study was to investigate the relationship between depressive and positive symptoms, two positive symptom using scales (PANSS and SAPS) in samples defined by three schizophrenic diagnostic systems (DSMIII-R, ICD9 and Langfeldt) at difference phases of the illness and in taking into account the negative and extrapyramidal symptoms and the doses of neuroleptics. With both scales, correlations between depressive and positive symptoms were significantly negative in two diagnostic subgroups (DSMIII-R and Langfeldt) in the acute phase. These correlations were also significant when negative symptoms, subjective extrapyramidal signs and the doses of neuroleptics were partialled out. Only the extrapyramidal physician's score was intercorrelated with positive and negative symptoms. Among the positive symptoms, 'conceptual disorganization' (or 'positive formal thought disorder') and 'suspiciousness/persecution' were especially correlated negatively with depression. At the post-acute phase or at the residual phase, no significant correlation between depressive and positive symptoms was found in any diagnostic subgroup. These results show the necessity of taking into account the phase of illness and the diagnostic criteria in order to study depression in schizophrenia.