15:00 THE RELATIONSHIP OF SUBCLINICAL PSYCHOTIC EXPERIENCES TO INTERNALISING AND EXTERNALISING PSYCHOPATHOLOGY IN CHILDHOOD

Abstract

Background: Subclinical psychotic-like experiences (PLEs) are common among the general population, particularly in children. Nevertheless, they confer elevated risk for later psychotic illness. This risk might be increased only in the context of additional psychosis risk markers, with recent research highlighting associations between depression/anxiety and the persistence of PLEs during adolescence. Yet, schizophrenia and related disorders are predicted by childhood externalising (EXT) as well as internalising (INT) psychopathology. Thus, the present study examined the latent structure underlying PLEs, EXT, and INT symptoms in a community sample of children aged 9-11 years. The study further examined whether longitudinal PLE trajectories over two years, particularly PLE persistence, predicted the presence of later INT and EXT problems. Methods: A community sample of 7,966 children (95% of eligible children; 51% male; mean age 10.4 years) completed questionnaires in class that assessed nine PLEs, EXT symptoms (conduct problems, hyperactivity and INT symptoms (emotional problems and peer relationship problems). A subsample of 547 children (46% male, mean age 12.2 years) completed reassessment after an average of two years, with their caregivers additionally reporting on children’s INT and EXT symptoms at both times (T0 and T1). Data in the longitudinal analysis were weighted to reflect the baseline population sample. Factor analysis of child-reported data in the large community sample (T0) was conducted to determine the latent structure underlying PLEs and other psychopathology in the general child population. In the longitudinal analysis, four PLE trajectories were defined using child-reported PLEs: persistent (PLEs at T0 and T1); remitting (PLEs at T0, but not at T1); incident (no PLEs at T0, but PLEs at T1); and none (no PLEs at T0 or T1). These trajectories were used to predict the presence of child-/parent-reportedINT and EXT problemsat T1. Analyses were repeated after correcting for age, sex, duration of follow-up, and T0 INT and EXT problems. Results: Two thirds (66%) of children aged 9-11 years reported at least one PLE at T0, with individual prevalence on the nine items ranging between 9-35%. All nine PLE items loaded on a single psychotic-like construct, which was discriminable from, though correlated with, latent dimensions representing INT and EXT problems. PLE trajectory prevalence rates over two years were: persistent 25%, remitting 39%, incident 5%, none 31%; with a majority of the children who reported a PLE at T0 no longer doing so at T1 (61%). Children whose PLEs remitted presented comparable rates of T0 and T1 INT or EXT problems to their peers who never presented PLEs. Children whose PLEs persisted were more likely to present T1 INT and EXT problems than their peers who never presented PLEs (INT odds ratio [OR]=3.1; EXT OR=2.4), as well as children whose PLEs remitted (INT OR=1.8; EXT OR=1.8). These associations remained after correcting for potential confounders and prior (T0) INT and EXT psychopathology. Discussion: Among the general childhood population aged 9-11 years, PLEs are common, though transient in the majority. Assessing PLEs at this age is viable, and permits delineation of a subset of children whose PLEs persist two years later, during transition to adolescence. PLE persistence relates to later externalising and internalising problems. Thus, interventions to reduce emotional and behavioural problems might target children presenting persistent PLEs, with some requiring additional strategies to ameliorate anxiety and depression symptoms, and others, behavioural and attentional problems.