Neurological soft signs and schizotypal dimensions in unaffected siblings of patients with schizophrenia

The objectives were to determine the neurological soft signs (NSS) scores in unaffected siblings of patients with schizophrenia compared with healthy controls and to examine their relationships with schizotypal dimensions. Participants comprised 31 unaffected siblings of patients with schizophrenia and 60 healthy controls matched according to age, gender and school level who were assessed by the Schizotypal Personality Questionnaire (SPQ) and the Krebs et al. NSS Scale. Higher NSS total scores and sub-scores were found in the unaffected siblings compared with the controls. The SPQ total score was significantly higher in unaffected siblings compared with control subjects. The NSS total score was positively correlated with the SPQ total score and the SPQ disorganization sub-score in unaffected siblings of patients with schizophrenia. Additionally, in unaffected siblings, motor coordination and integration abnormalities were positively correlated with the SPQ total score and the cognitive-perceptual sub-score. Motor integration abnormalities were also correlated with the SPQ disorganization sub-score. These results reveal that NSS, especially motor signs, are associated with some schizotypal dimensions in siblings of patients with schizophrenia, suggesting the value of using both assessments to study high risk populations.