204s Categorical anddimension approaches in schizophrenia

848. Categorical and dimensionapproaches in schizophrenia

Chairmen: S Dollfus, P Berner

CONCEPTUALISATION OF SCHIZOPHRENIA: THESYMPTOM·ORIENTED APPROACH

P. Berner. Universttdtsklinik flir Psychiatrie, Wiihringer Gurtel18-20, A-1090, Vienna, Austria

E. Bleuler presumed that nearly all symptoms of dementia praecoxrepresent reactions to the illness process but that some of them areparticularly linked with the basic disturbance. He suggested that theidentification of such fundamental symptoms could lead the discov­ery of specific impairments. But the assumption that fundamentalsymptoms are not mutually independant incited to base research onsamplescomprising all patients presentingat least one of the varioussymptoms suspected to be fundamental. K. Schneider's proposal tobase the diagnosis of schizophrenia on the presence of symptomsrecognizable without difficulty represents a similar syndromaticapproach. Modem classifications include at choice Bleuler's fun­damental and Schneiders first rank symptoms in their diagnosticcriteria. This may lead to erroneous attributionsin viewof the possi­bility that mostof the firstrank symptomsand someof the symptomsBleuler suspected to be fundamental may be unspecific reactionsto different basic etiologies. It can be expected that research basedon symptoms is better suited to resolve this problem. Results ofrecent symptom-oriented studies in particular those investigating therelationship between formal thought disorders and specificcognitiveimpairments are discussed.

HETEROGENEITY IN SCHIZOPHRENIA: IDENTIFYINGSUBTYPES BY CLUSTER ANALYSES

S. DoIJfus. P. Brazo. CentreEsquirol, CentreHospitalierUniversitaire, Cote de Nacre, Caen, 14000, France

The negative-positive dichotomy in schizophrenia seems to be anoversimplification since other subtypes such as mixed, disorganizedand residual have been individualized in a previousstudy (Dollfus etal, 1996).

The aim of this study was to test the stability of this subtypologyof schizophrenia by using a particular method of cluster analysis ona larger data set. The Ward's method was applied to the PositiveAndNegative Syndrome Scale (PANSS) score of 198 patients, definedas schizophrenic by one of the three diagnosticcriteria (DSMIII-R,Feighner,ROC).

The results suggest the existence of at least 3 subtypes (positive,negative and mixed) of schizophrenic patients independently of thephase of illness (chronic, acute) and 2 subtypes which vary withthe phase of illness: a residual subtype was observed in patients instabilized phase whereas a positive non-disorganized subtype wasdisplayed in patients in an acute phase. The former subtype hadnot particular characteristics compared to others whereas the lattersubtype was characterized by a late onset of illness (rn ± OS =49.8± 20.2), a prevalence offemale (84.6%) and a good outcome.

This study shows the stability of the positive,negative and mixedclusters which shows the oversimplification of the negative-positivedichotomy in schizophrenia.

THE DEFICIT SYNDROME OF SCHIZOPHRENIA:TOWARDS HETEROGENEITY OF SCHIZOPHRENIA?

M. Petit, F.Thibaut, J.M. Ribeyre. University ofRouen; ER 304.Centre Hospitalier du ROUVTO}: 4 rue PaulEluard, 76301Sotteville-les-Rouen

From Kraepelin's (\896) and Bleuler's (\907-1911) first descrip­tions to recent studies, several authors have debated the question ofunity or diversityof schizophrenia. Within this context, the negativesymptoms have generated major interest and some authors (Crow,Andreasen,Kay) classified schizophrenia according to the presenceor absence of negative symptoms. Based on Kraepelin's clinicaldescription, Carpenter et al. (\ 988) proposed another subtyping:the deficit symptoms which refers to the presence or absence ofprominent primary enduring negative symptoms. Primary negativesymptoms have to be inherent to schizophrenia itself, in otherwords they must not derivate from factors such as depression.anxiety, akinesia... B. Kirkpatrick et at. (\ 989) have proposed the"Schedule for the Deficit Syndrome (SOS)" to reliably identify thedeficitsyndromeconcept. Deficitpatients as comparedto non deficitpatients. share neurological, neuropsychological, brain imaging im­pairments biochemical and therapeutical characteristics supportingthis subtyping.

FACTOR ANALYSIS AND STRUCTURAL MODELS OFSCHIZOPHRENIA

LeonardWhite. DepartmentofPsychiatry, Mt. Sinai SchoolofMedicine. West Brentwood, NY. 11717, USA;Pilgrim PsychiatricCenter, BoxA, West Brentwood, NY, 11717, USA

The Positiveand Negative Syndrome Scale (PANSS)was conceptu­alized as an objectivemethodfor evaluating 30 symptomsthat definethree syndromes of schizophrenia: positive, negative and generalpsychopathology. Additionally. the scale contains five (actors asdescribed in the widelyused Brief PsychiatricRating Scale (BPRS).Based upon exploratory factor analytic studies of the PANSS it hasbeen suggestedthat (our or as manyas fivefactors may be necessaryto describe the syndromes of schizophrenia. Confirmatory factoranalysis, based upon structural modeling, provides for a statisticaltest of the adequacy of alternative factor structures. We report astudy using the methodof confirmatory factor analysis to determinewhichof eleven alternative factorial models provides the best fit forPANSS rated symptoms of schizophrenia. The sample (N = 1233)was obtained by poolingdata across fivecenters. All a priori modelsfailed to meet criteria for a good fit to the empirical data. Of elevenfactor modelsevaluated, the best filling alternative was the modifiedfive factor solution proposed by Lindenmayer et al. 1995 (RobustCFI =0.827). Since the lack of fit was not attributable to I. Poorreliability 2. low variances or 3. small sample size. we concludethat modifications in the PANSS are required if the scale is to beused to generate an adequate structural model for the symptoms ofschizophrenia.