Family transmission of positive and negative symptoms in familial and sporadic schizophrenia

Abstract

Introduction. A genetic component is recognized as a cardinal feature in the etiology of schizophrenia that is presently conceived as a complex disease. However, identifying its molecular bases has become a problem, mainly due to the difficulties that the schizophrenic phenotype presents. The aim of this study is to determine whether the positive and negative symptoms are differentiated from each other according to family history in a family study using familial/sporadic strategy.

Methods. 601 subjects were studied (196 schizophrenics, 205 first degree relatives and 200 controls). A SCAN system and the diagnosis criteria of DSM IV were used. For the familial study the FIGS and PANSS scales were applied. Families were grouped into familial or sporadic groups according to family aggregation. Comparisons were made using the ANOVA.

Results. The groups of patients and the first degree relatives with familial schizophrenia showed significantly higher scores in the negative sub-scale than did the sporadic schizophrenia subjects. Behavior of the first degree relatives with sporadic schizophrenia was similar to the control group. Positive sub-scale scores and general psychopathology showed no differences in the patients and their relatives according to familiar aggregation.

Conclusions. This study confirms previous results that negative symptoms are more frequent in schizophrenics and their first degree relatives with familial schizophrenia. Therefore, it can be said that negative symptoms are a clinical phenotype more related to the genetic etiology.