Longitudinal Trajectories of Clinical Features in Community Youth With Recurrent Psychosis Spectrum Symptoms: Findings From the Philadelphia Neurodevelopmental Cohort.

Background And Hypothesis: In the general population, more severe, recurrent subthreshold psychosis spectrum (PS) symptoms are associated with a heightened risk of poor outcomes. Here, we expanded and temporally extended our prior 2-year follow-up of community youth with recurrent PS symptoms in the Philadelphia Neurodevelopmental Cohort (PNC) by characterizing longer-term trajectories of symptom domains and global functioning compared to youth with other recurrent psychopathology.

Study Design: The PNC Time 1 included 9498 community youth (age 8-21) recruited from a pediatric healthcare network. A subsample (n = 752) participated in prospective evaluations (mean visits = 2.75; interval range years first:last visit = 0.2:9.3; mean = 4.52 years; age range years first:last visit = 8.1-21.9:9.5-29.9). Youth were classified based on psychopathology at first and last visits. Longitudinal trajectories of symptom domains (positive, negative, disorganized, general) and global functioning were modeled using generalized additive mixed models.

Study Results: Youth with recurrent PS displayed a nonlinear developmental trajectory of positive psychosis symptoms such that severity increased slowly until the early 20s, and then briefly plateaued before increasing significantly in the late 20s. They also exhibited increases over time in disorganized and negative symptoms, and in general symptoms, which were lower in severity and relatively stable in other groups. Global functioning in recurrent PS declined from moderate to serious impairment over time, compared to youth with recurrent other psychopathology, where higher and more stable functioning was observed.

Conclusions: Results underscore that PS symptoms in community adolescents reflect dynamic developmental processes into early adulthood, and support evaluating trajectories of multiple symptom and functional domains.