Symptoms of Attenuated Psychosis Syndrome in Relatives of Clinical High-Risk Youth: Preliminary Evidence

Abstract Background and Hypothesis Attenuated Psychosis Syndrome (APS) impacts functioning and predicts increased risk of psychosis. Risk for developing APS itself has received minimal attention. Knowledge of familial and environmental contributions to APS symptoms would advance understanding of APS and risk for psychosis. As an initial step, this report presents the first data on APS symptoms in family members of APS patients. Study Design This study utilized a discordant sibling-pair family study design. The Structured Interview for Psychosis-risk Syndromes (SIPS) was administered to 17 APS probands and 26 non-APS biological siblings. Probands and siblings were compared on positive, negative, disorganized, and general SIPS symptom scales and factors derived from those scales. Study Results There was significantly greater symptom severity in probands compared to siblings on nine of 19 SIPS scales. Negative/anxiety, functioning, and positive symptom factors were identified. Probands showed significantly greater severity than siblings on the negative/anxiety and positive factors. Elevated pathology on the negative/anxiety factor best differentiated between probands and siblings, over and above the contribution of the positive factor. No difference was found for the functioning factor. Conclusions Results support the importance of non-familial effects on risk for APS and suggest differences in familial contribution to APS symptoms. Understanding the relative contribution of familial and environmental effects on APS symptoms may reveal important differences among APS patients, with implications for risk characterization, symptom course, and treatment selection.