Dynamic association between interpersonal functioning and positive symptom dimensions of psychosis over time: a longitudinal study of healthy adolescents.

Background: Cross-sectional studies have indicated that alterations in social functioning, particularly interpersonal functioning, are associated with the occurrence of psychotic symptoms and experiences at different levels of the extended psychosis phenotype (ranging from population psychometric expression of liability to overt psychotic disorder). However, more research is needed on the development of this association over time. Methods: Cross-lagged path modeling was used to analyze bidirectional, longitudinal associations between 4 dimensions of subclinical psychotic experiences (persecutory ideation, bizarre experiences, perceptual abnormalities, and magical thinking) and interpersonal functioning in an adolescent general population sample (N = 881 at T1, N = 652 at T2, and N = 512 at T3) assessed 3 times in 3 years. Results: All symptom dimensions showed some association with interpersonal functioning over time, but only bizarre experiences and persecutory ideation were consistently and longitudinally associated with interpersonal functioning. Poorer interpersonal functioning predicted higher levels of bizarre experiences and persecutory ideation at later measurement points (both T1 to T2 and T2 to T3). Conclusions: Poor interpersonal functioning in adolescence may reflect the earliest expression of neurodevelopmental alterations preceding expression of psychotic experiences in a symptom-specific fashion.