An Investigation of the Psycho-Social Risk Factors and Associated Outcomes of Psychotic Experiences in Early Adolescence

Background: Psychotic experiences (PEs) are common in adolescence and are associated with poorer psychiatric outcomes. The nexus between PEs, mental disorder and psychosocial outcomes is poorly understood. The aims of this thesis were three-fold. Firstly, I investigated if psychosocial data predicts adolescent PEs (Study-I) and if changes in self-concept alters the risk of PEs (Study-II). Secondly, I examined the published literature investigating the relationship between childhood PEs and mental disorder (Study-III), investigated if PEs improved the prediction of subsequent psychopathology (Study-IV) and investigated if children who report PEs have poorer functioning into adulthood (Study-V). Lastly, I examined whether malleable psychosocial variables mediate the relationship between PEs and subsequent psychopathology (Study-VI).

Method: I conducted five secondary analyses of longitudinal observational data and one systematic review. I used data from the Adolescent Brain Development (ABD) Study and Cohort 98’ from the Growing-Up in Ireland (GUI) study. The ABD study (ages:12-18) included clinical interview and self-report data. The GUI (ages:9-18) included survey questionnaire data. The systematic review was conducted by two reviewers. Statistical analyses included machine learning methods, logistic regression, mixed-model analysis and traditional and counter-factual mediation.

Results: Psychosocial characteristics adequately predicted subsequent PEs (Area Under the Curve:0.61, Study-I). Changes in self-concept vastly altered the odds of adolescent PEs (Study-II). Children reporting PEs had a 4-fold increased odds of a psychotic disorder (Population Attributable Fraction: 23%) and a 3-fold increased odds of non-psychotic disorders (Study-III). PEs improved the prediction of subsequent externalising problems beyond established markers (Study-IV). Children reporting PEs had persistently poorer functioning into adulthood (Study-V). Self-concept and parent-child conflict mediated between 13-52% of the longitudinal relationship between PEs and non-psychotic psychopathology (Study-VI).

Discussion: PEs are interconnected with poorer psychiatric and psychosocial outcomes. Based on the evidence, PEs appear to be a marker of global vulnerability to psychiatric distress that occurs in the context of psychiatric and psychosocial hardship. Assessing PEs improves the prediction of subsequent psychopathology. Finally, our evidence suggests that, in the presence of early adolescent PEs and non-psychotic psychopathology, interventions targeting self-concept and parent-child conflict may reduce the incidence of subsequent psychiatric outcomes.