T37. PREPULSE INHIBITION IN UNAFFECTED SIBLINGS OF SCHIZOPHRENIA AND CLINICAL-HIGH RISK WITHOUT FAMILY HISTORY OF PSYCHOSIS

Abstract

BackgroundIt is reported that prepulse inhibition (PPI) deficiency of startle reflex in schizophrenia is associated with positive symptoms and is hereditary. In this study, the perceived spatial separation (PSS) induced-prepulse inhibition paradigm based on the priority effect effectively was used to explore PPI levels of genetically high-risk (GHR) of schizophrenia and clinical high risk (CHR) without family history of psychosisMethodsWe examined startle magnitude and PPI in38 CHR (No family history of psychosis), 28 GHR (Siblings or children of schizophrenia), and 44 healthy controls (HC). Modified acoustic PPI paradigm included PSS-PPI and perceived spatial co-location PPI (PSC-PPI) with inter-stimulus interval (ISI) of 60 or 120ms. The Structured Interview for Psychosis risk Syndromes (SIPS) and MATRICS Consensus Cognitive Battery (MCCB) was used to measure psychotic symptom and neuropsychological state of individualsResultsUsing gender, age, and smoking as covariates, Covariance analysis for modified PPI level results revealed that there were significant differences in PSSPPI60 (F = 6.25, p = 0.03) and PSSPI120 (F = 6.57, p = 0.03) paradigm between the three groups. Compared with HC, PSSPPI paradigm detected PPI defects of CHR individuals at 60ms ISI (F = 14.25, p ＜0.001) and 120ms ISI (F = 14.01, p ＜0.001). PPI deficiency was not detected in GHR individuals. PPI level in both groups were unrelated to demographics, clinical characteristics, and cognition. Using GLM analysis, the interaction between grouping and experimental paradigm had no significant effect on PPI level at 60ms (F = 1.88, P = 0.16) and 120ms (Z = 1.66, P = 0.19).DiscussionIt seems that mere heritability of psychosis is not enough to produce PPI defects, which may be related to the progression of psychosis