Differential diagnosis and diagnostic systems in schizophrenia

Diagnosis and prognosis are critical issues confronting psychiatry. In order to answer the fundamental questions concerning the origin and development of schizophrenia, we must first be clear about what it is. We must be able to separate the illness of schizophrenia from other disorders (see Fig. 1). We have attempted in this article to examine some of the illnesses that may resemble schizophrenia and make its discrimination difficult. We hope that by discussing these disorders and their similarities to schizophrenia the important issues and dilemmas have become clearer and more readily understood by the clinician. Future studies assessing the validity of diagnostic systems for schizophrenia may have to rely on features other than cross-sectional symptoms and longitudinal course. Such characteristics as pharmacologic responsivity and genetic transmission and the development of biologic markers may be the prospective cornerstones for validating the diagnosis of schizophrenia.     

Testing systems for assessment of negative symptoms in schizophrenia.

To compare methods of measuring negative symptoms, eight rating scales were employed to retrospectively assess and subtype 187 patients with schizophrenia from the Chestnut Lodge Follow-up Study. These included Andreasen's Schedule for Assessment of Negative Symptoms, Carpenter's Criteria for the Deficit Syndrome, Kay and Opler's Positive and Negative Symptom Scale, the scales developed by Krawiecka et al and Crow's modification of them, the Negative Symptom Scale developed by Lewine et al, Pogue-Geile and Harrow's Negative Symptom Scale, and Abrams and Taylor's Emotional Blunting Scale. The overlap and concordance, temporal stability, and predictive validity of these instruments are described. When rated from detailed medical records, the reliability of all scales was fair to good. Despite their inclusion of different items, there were high positive correlations between the scales when used to rate negative symptoms dimensionally. When used to classify individual patients as having the negative or deficit syndrome, however, concordance among criteria was low. Using the broadest criteria (Pogue-Geile and Harrow), 75 (40%) patients were diagnosed as having negative syndrome; the narrowest criteria (Andreasen and Olsen) yielded 11 (6%) diagnoses of negative syndrome. Narrower definitions tended to be subsets of broader ones. Carpenter's Criteria for the Deficit Syndrome focus on primary enduring negative symptoms and show the greatest temporal stability. Broader criteria, which diagnose the deficit or negative syndrome independent of severity of positive symptoms, had the greatest predictive validity.     

Comparison of four diagnostic systems for the diagnosis of somatization disorder

This article compares the Feighner criteria, the DSM-III criteria for somatization disorder and a modified version of the proposed ICD-10 criteria. Working with a data set collected from the charts of 250 patients considered likely to have unexplained somatic symptoms, the kappa statistic and percentage agreement was calculated. The kappa between the DSM-III and DSM-III-R criteria is 0.93. Between the modified ICD-10 and DSM-III it was 0.71, but between Feighner and the modified ICD-10 it was 0.44. However, the different criteria identify the same patient population based on mental co-morbidity and demographics. The authors suggest that the modified version of the proposed ICD-10 should be investigated further, as it can use data sets previously collected for assessments of somatization disorder.     

Outcome of schizophrenia in India using various diagnostic systems

A group of 112 patients diagnosed to be suffering from schizophrenia according to ICD-9 concept of this disorder were followed-up for a period of 18-30 months. Five diagnostic systems for schizophrenia: CATEGO, Research Diagnostic Criteria, Feighner's Criteria, DSM-III and Schneider's First Rank Symptoms were also applied to the study group at the beginning of the investigation. The outcome was assessed in the areas of clinical improvement, course, severity of illness and work. The course of the disorder and outcome in various definitions did not reveal significant variability though patients diagnosed to be schizophrenics according to DSM-III tended to display more psychopathology and impaired work efficiency at the time of follow-up.     

A comparison of five diagnostic systems for childhood schizophrenia and infantile autism

Five diagnostic systems designed to differentiate infantile autism and early childhood schizophrenia were compared by deriving scores on 44 children referred consecutively to the same clinical center. While the autistic scales devised by Rimland, Polan and Spencer, Lotter, and the British Working Party correlated significantly, the degree of correspondence (35%) indicated that several children obtained high autistic scores in one system but low scores in another. The BWP's term schizophrenia has more correspondence with the term autism used by others than with Rimland's schizophrenia. In the DeMyer-Churchill categorical system (early schizophrenia, primary autism, secondary autism, and non-psychotic subnormal), primary autism most resembles Rimland's concept of infantile autism as measured by his E-1 version. All other systems differentiate psychotic from non-psychotic children but do not distinguish any of the psychotic subgroups.This study was supported in part by Public Health Service Grant No. MH05154 and also by LaRue D. Carter Memorial Hospital, State of Indiana, Indianapolis, Ind.The authors wish to thank Dr. Bernard Rimland for providing his scoring key.     

Outcome of schizophrenic subtypes defined by four diagnostic systems

This report examines the short- and long-term outcome of the subtypes of schizophrenia as defined by four diagnostic systems: DSM-III, Research Diagnostic Criteria, Ninth Revision of the International Classification of Diseases, and the Tsuang-Winokur (T-W) criteria. Patients were from the Iowa 500 study and met Washington University criteria for schizophrenia. Subtype diagnosis was based on extensive chart material reviewed by investigators blind to outcome. Short-term outcome, based on chart information, and long-term outcome, based on individual field follow-up, were both better for paranoid than for nonparanoid schizophrenia, the difference being greatest using the T-W criteria. The difference in outcome between paranoid and nonparanoid schizophrenia was greater at long-term than at short-term follow-up, and greater using residential and occupational than psychiatric outcome criteria. Outcome did not differ for the two common forms of nonparanoid schizophrenia: hebephrenic and undifferentiated. The subtyping of schizophrenia has important predictive validity, which was greatest using the T-W criteria.     

Advantages of abandoning symptom-based diagnostic systems of research in schizophrenia

An alternative is suggested to the symptom-based diagnostic conceptualizations of schizophrenia that are now general. Using a different methodological philosophy, it would investigate empirically determined underlying structure. It is proposed that studies should be more clearly directed toward linking symptoms, underlying processes, and etiology.     

Evolution of diagnostic criteria for schizophrenia

Many operational diagnostic criteria for schizophrenia, which are rooted to various degrees in the concepts of Kraepelin, E. Bleuler and K. Schneider, have been developed during the last two decades. They often incorporate prognostic factors to which Langfeldt in particular had drawn attention. These recent criteria vary considerably according to the attitude taken with regard to Jasper's hierarchical principle, which accords a diagnostic superiority to schizophrenic symptoms over affective symptomatology. Attribution to schizophrenia is very different depending upon whether the systems uphold, reject or reverse this principle. One should distinguish between classifications based upon a consensus of experts or experienced clinicians on the one hand and diagnostic research criteria destined to test etiopathogenetic hypotheses on the other. The important principles of attribution of DSM III and DSM III-R are outlined as well as their shortcomings, the latter leading to the conclusion that one should not restrict oneself to employ solely the American classification, but utilize it along with other classifications, such as the French empirical criteria or the Vienna research criteria, in order to see more clearly whether the very broad definitions of schizophrenia do not camoufly particular etiopathogenetic entities which ought to be identified.     

The borderline syndrome. I. Testing three diagnostic systems

Diagnostic systems require testing on several factors: reliability, comprehensiveness, concordance with established use, specificity, and validity. Three sets of diagnostic criteria for the borderline have been proposed recently: the Gunderson et al criteria, the DSM-III criteria for borderline personality (BP) disorder, and the DSM-III criteria for schizotypal personality (SP) disorder. This article reviews work to date testing these systems on these factors. New data are presented from the retrospective application of these criteria to the clinical records of 400 diagnostically heterogeneous former inpatients at Chestnut Lodge, Rockville, Md; 330 of them also received systematic follow-up by interview an average of 15 years after discharge. Results strongly supported the validity of the DSM-III division of borderline into BP and SP. Although the BP and Gunderson et al criteria demonstrated high concordance, the latter appeared to offer some slight advantages for defining BP disorder.     

The underlying structure of diagnostic systems of schizophrenia: a comprehensive polydiagnostic approach

The objective was to ascertain the underlying factor structure of alternative definitions of schizophrenia, and to examine the distribution of schizophrenia-related variables against the resulting factor solution. Twenty-three diagnostic schemes of schizophrenia were applied to 660 patients presenting with psychotic symptoms regardless of the specific diagnosis of psychotic disorder. Factor analysis of the 23 diagnostic schemes yielded three interpretable factors explaining 58% of the variance, the first factor (general schizophrenia factor) accounting for most of the variance (36%). On the basis of the general schizophrenia factor score, the sample was divided in quintile groups representing 5 levels of schizophrenia definition (absent, doubtful, very broad, broad and narrow) and the distribution of a number of schizophrenia-related variables was examined across the groups. This grouping procedure was used for examining the comparative validity of alternative levels of categorically defined schizophrenia and an ordinal (i.e. dimensional) definition. Overall, schizophrenia-related variables displayed a dose-response relationship with level of schizophrenia definition. Logistic regression analyses revealed that the dimensional definition explained more variance in the schizophrenia-related variables than the alternative levels for defining schizophrenia categorically. These results are consistent with a unitary and dimensional construct of schizophrenia with no clear "points of rarity" at its boundaries, thus supporting the continuum hypothesis of the psychotic illness.     

Research in schizophrenia: necessity to include patients of multiple diagnostic systems]

The discrepancies of studies on symptomatology and treatment of schizophrenia could be related to the selection of different patients diagnosed by one diagnostic system, different from a study to another. Therefore, we tested whether 14 diagnostic systems could include 51 patients differently as regard to the intensity of positive, negative or depressive symptomatology and to the phase of illness. The distribution of the patients in different sets of diagnosis has been carried out by a computer program and the symptomatology has been evaluated with PANSS and MADRS. Some diagnostic criteria like DSMIII-R, Langfeldt, Taylor, ICD 9 include negative and depressive patients preferentially. Others systems like Berner, Catego, ICD 9, New-Haven, Schneider, include more patients with acute than residual symptoms. These results show the importance of the choice of one or more diagnostic criteria depending on the aim of the study.     

Testing new diagnostic criteria for hypomania.

BACKGROUND: A recent series of studies has questioned DSM-IV diagnostic criteria for hypomania, suggesting that overactivity (increased goal-directed activity) should have priority over mood change as stem criterion. Angst has suggested new criteria for hypomania, giving priority to overactivity. Study aim was to test the validity of Angst's diagnostic criteria for hypomania. METHODS: A consecutive sample of remitted 213 DSM-IV bipolar-II disorder (BP-II) and major depressive disorder (MDD) outpatients were re-diagnosed, during a follow-up visit, by the Structured Clinical Interview for DSM-IV (yes/no structured questions on hypomanic symptoms, skip-out instruction of stem question on mood change not followed, in order to assess all past hypomanic symptoms), by a mood disorder specialist psychiatrist in a private practice. Angst's stem diagnostic criteria for hypomania were tested versus DSM-IV hypomania: 1) overactivity plus at least 3 of the 7 DSM-IV hypomanic symptoms 2) overactivity plus at least 2 of the 7 DSM-IV hypomanic symptoms. RESULTS: DSM-IV criteria for hypomania were met by 137 patients, overactivity plus 2/7 was met by 146 patients, and overactivity plus 3/7 was met by 135 patients. Of the patients with overactivity plus 2/7, 83.5% also met DSM-IV criteria for hypomania, and of the patients with overactivity plus 3/7 86.6% also met DSM-IV criteria for hypomania. Logistic regression of DSM-IV hypomania versus overactivity plus 2/7 found odds ratio (OR) = 17.6, and versus overactivity plus 3/7 found OR = 18.8. Comparisons between DSM-IV hypomania and Angst's criteria for hypomania showed that there were no significant differences on age, gender, symptom structure of hypomania, number of episodes, episodes duration, and episodes level of functioning. Associations (ORs) between the stem criterion of each definition of hypomania and hypomanic symptoms were often strong. DSM-IV hypomania stem criterion was closely associated with overactivity (OR = 15.4), and Angst's hypomania stem criteria were closely associated with mood change (OR = 7.6 for overactivity plus 2/7, OR = 14.3 for overactivity plus 3/7). CONCLUSIONS: Results support Angst's criteria for hypomania based on overactivity (overactivity plus 3/7 seems more supported). These criteria do not seem to lead to overdiagnosing hypomania. Previous studies supported the upgrading of overactivity among DSM-IV hypomanic symptoms. Angst's diagnostic criteria may positively impact the treatment of depression. It has been shown that focusing the probing for history of hypomania more on overactivity than on mood change reduces the false-negative BP-II. By using Angst' criteria for hypomania, clinicians may reduce the current high misdiagnosis of BP-II as MDD and the related mistreatment.     

Basal and haloperidol-stimulated prolactin in neuroleptic-free men with schizophrenia defined by 11 diagnostic systems

Forty-four male, neuroleptic-free, acutely psychotic patients with at least one diagnosis of schizophrenia among 11 diagnostic systems, and 28 healthy controls, underwent measurement of prolactin (PRL) concentrations before and after intravenous administration of haloperidol (0.5 mg). Basal PRL concentrations were lower in the patients with Research Diagnostic Criteria (RDC) DSM-III, Cloninger, and Taylor and Abrams schizophrenias than in controls. Compared with the controls, the PRL response to haloperidol was lower in the patients with schizophrenia defined by all diagnostic systems except those of Schneider and M. Bleuler. Neither basal nor stimulated PRL concentrations were correlated with positive symptoms, but basal PRL was correlated with the Brief Psychiatric Rating Scale (BPRS) depression-related subscore. This study lends further support for the presence of dopaminergic dysfunction in schizophrenia, and demonstrates the advantages and problems in the use of multidiagnostic psychopathological evaluation to categorize a disorder where there is major disagreement among diagnostic systems.     

Comparative evaluation of research diagnostic criteria for schizophrenia.

Criteria for establishing a diagnosis of schizophrenia have been proposed by several different authors. This study compared six different research diagnostic criteria (RDC) in a series of 166 patients who received a clinical diagnosis of schizophrenia in a multicenter study. The alternative criteria differed in the proportion of clinical diagnoses that were confirmed, with the Washington University (Feighner) criteria accepting only 26%. The criteria also disagreed concerning which particular patients qualified for the diagnosis. The Washington University and New York RDC disagreed 50% of the time, and some other disagreement rates were even higher. More evaluative research is needed before arbitrary criteria are permitted to redefine the concept of schizophrenia.     

Long-term stability of subtypes in schizophrenic disorders: A comparison of four diagnostic systems

Summary The long-term stability of subtypes of schizophrenic disorders in 148 narrowly defined schizophrenic patients according to four diagnostic systems was compared. The patients were investigated longitudinally for 23 years on average (range 10–50 years). Patients who experienced only one episode and those who were permanently hospitalised were excluded on methodological grounds. Of the remaining 100 patients, a total of 461 episodes were classified into various subtypes according to the criteria of DSM-III-R, ICD-10, the positive/negative dichotomy, and Schneider's first-rank symptoms. It was found that long-term stability of subtype in schizophrenic disorder was not the rule but the exception. The frequency of stable course was found to be depend on the type of the initial episode. In most cases a subtype change occurred within the first few years of the illness with no clear direction. In later stages of the illness the relative frequency of episodes predominated by negative symptomatology increased. The findings were similar for DSM-III-R, ICD-10 and positive/negative dichotomy. Only in patients beginning without first-rank symptoms were more stable than non-stable courses found. The results of this study do not support the assumption that stable subtypes are nosological or etiopathogenetic subentities of schizophrenic disorders.     

Recovery and systems transformation for schizophrenia.

The Recovery Movement, initiated in the 1990s by mental health consumer groups and leaders, has emerged as a major force in the mental health field. This movement has been gaining strength and promises to impact mental health service delivery through innovations in care that other models of care have not offered. Recent efforts to conceptualize and study recovery empirically have bolstered the movement from a scientific standpoint. This article reviews the growing literature regarding recovery, offers a conceptual framework for understanding recovery, and discusses a specific manner in which systems transformation has begun to occur.