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27. Developmental and Sex Influences on Symptom Expression in First Episode Psychosis
Introduction: While the neurodevelopmental model of psychosis gains increasing support, the developmental influence on psychotic symptom expression – how a person’s age affects his or her clinical presentation in first-episode psychosis – has not been thoroughly investigated. Understanding developmental influences across the lifespan in first-episode psychosis may lead to the creation of developmentally-informed assessment and treatment practices. Furthermore, these findings may help elucidate how pathological brain-behavior relationships vary as a function of development. Methods: Using generalized additive modeling (GAM), which allows for linear and non-linear models, we leveraged symptom data from a large sample of individuals experiencing a first episode of psychosis (FEP, N=430, ages 12-40 years), collected at the University of Pittsburgh from 1990-2017. We examined: 1) the relationship between age and severity of perceptual and non-perceptual positive symptoms, 2) potentially distinct developmental trajectories of negative symptom presentation, and 3) the influences of sex on these trajectories. Results: Perceptual positive symptoms significantly decreased with increasing age in females (F=5.8, p=4.5-e07, q=3.2e-06), particularly between 12 to 14 years of age, but were stable in males. In contrast, non-perceptual positive symptoms (i.e., delusions), increased with age (F=3.2, p=0.01, q=0.03) in males only. Total negative symptoms significantly decreased in females, particularly at 12-16 years of age (F=2.9, p=0.002, q=0.009) but remained stable in males. All relationships remained significant when cognitive functioning, parental socioeconomic status, illness duration, and antipsychotic medication use were included in the model. Conclusions: There are important sex differences in the developmental emergence of psychosis with females showing dynamic decreases in perceptual symptoms through adolescence in contrast to males who show targeted escalation of delusions. These findings inform potential neurodevelopmental mechanisms of psychosis and highlight the importance of considering an individual’s developmental stage and sex when presenting with psychosis.