Positive and negative symptoms in affected sib pairs with schizophrenia: Implications for genetic studies in an African Xhosa sample
Date
2005
Authors
Niehaus D.J.H.
Koen L.
Laurent C.
Muller J.
Deleuze J.-F.
Mallet J.
Seller C.
Jordaan E.
Emsley R.
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
Careful phenotyping and the identification of subtypes of schizophrenia can contribute significantly to the success of genetic studies in schizophrenia. The phenomenology of schizophrenia in affected sib pairs has been well-described in Caucasian populations, however a paucity of data exists for African populations. This study therefore investigated symptom dimensions in a sizeable group of affected Xhosa sib pairs as a means of evaluating the role of shared familial factors in the psychosis of schizophrenia. Five hundred and thirteen participants were interviewed with the Diagnostic Interview for Genetic Studies (DIGS), which included the Schedules for the Assessment of Negative and Positive symptoms (SANS/SAPS). One hundred and four sib pairs were then extracted (N = 208) for analysis of concordance for lifetime psychotic symptoms and an exploratory factor analysis of the SANS/SAPS. Concordance analysis of life-time symptoms indicated a significant concordance for olfactory hallucinations, persecutory delusions, jealousy, somatic, reference and control delusions as well as thought insertion and withdrawal. The factor analysis of the global scores of the SAPS and SANS revealed a five factor best-fit model and accounted for 92.5% of variance. The factors included a negative symptom factor, a positive symptom factor, a positive thought disorder and a bizarre behaviour component. The core symptomatology of schizophrenia in this sib pair sample was similar to that reported in Caucasian populations with the exception of higher rates of auditory hallucinations and delusions of persecution. In summary therefore; although the factor analysis only supported the concept of the universality of psychotic symptoms in schizophrenia, the concordance analysis of these symptoms did reveal hallucinations as well as delusions of control as possible candidates relevant for future research into genotype-phenotype relationships. © 2005 Elsevier B.V. All rights reserved.
Description
Keywords
adult, Africa, article, auditory hallucination, Caucasian, controlled study, delusion, factorial analysis, familial disease, female, genetics, human, interview, jealousy, lifespan, major clinical study, male, negative syndrome, olfactory hallucination, persecutory delusion, positive syndrome, priority journal, psychosis, psychosocial withdrawal, race difference, schizophrenia, sibling, somatic delusion, symptom, symptomatology, thought disorder, variance, Adult, Chi-Square Distribution, Demography, Factor Analysis, Statistical, Family Health, Female, Humans, Male, Middle Aged, Psychiatric Status Rating Scales, Schizophrenia, Schizophrenic Psychology, Severity of Illness Index, Sibling Relations, South Africa
Citation
Schizophrenia Research
79
03-Feb
79
03-Feb