Three types of psychotic-like experiences in youth at clinical high risk for psychosis

Background: A fully dimensional model of psychosis implies that psychotic-like experiences (PLEs) connect the entire psychosis spectrum. Three types of self-reported PLEs—persecutory ideation, bizarre experiences, and perceptual abnormalities—are commonly found in the general population. This study assessed the construct, predictive, and incremental validity of self-reported PLEs in youth at clinical high risk for psychotic disorders (CHR). Methods: Self-report data on PLEs (community assessment of psychic experiences; CAPE) were collected from 105 CHR youth (m_age = 19.3). Interview measures of attenuated psychotic symptoms and self-report measures of psychosis proneness, depression, and anxiety were collected at baseline and 12-month follow-up (n = 70 at follow-up). Factor, cross-sectional, and longitudinal analyses examined relationships between study variables. Results: Self-reported PLEs were best represented by the same three factors found in the general population: persecutory ideation, bizarre experiences, and perceptual abnormalities. Cross-sectionally, PLEs—particularly persecutory ideation—correlated with interview-rated attenuated psychotic symptoms and self-reported psychosis proneness, depression, and anxiety. Longitudinally, baseline PLEs trended toward predicting 12-month change in positive attenuated psychotic symptoms (r =.29, p_FDR =.058). Incrementally, baseline PLEs predicted 12-month change in positive and disorganized symptoms, when accounting for the effect of baseline positive symptoms and demographics. Conclusions: Three types of PLEs were valid in this CHR sample. Self-reported PLEs may be used not only to screen individuals for inclusion in the CHR classification, but also to characterize individuals within this population. Self-reported PLEs may help to forecast which CHR individuals will progress toward psychotic illness.