The Stability and Predictive Value of Negative Symptom Dimensions in First-Episode Psychosis: A 5-Year Follow-Up Study

Abstract Background Diminished Expression (DE) and Amotivation/Apathy (AA) are widely recognized as two main factors of negative symptoms. This study aimed to 1) examine the longitudinal stability of the DE-AA structure and its variation throughout a 5-year follow-up in people with first-episode psychosis (FEP), and 2) investigate whether DE and AA have distinct predictive value compared with the unitary construct of negative symptoms. Study Design 227 participants from the EUropean Network of National Schizophrenia Networks Studying Gene-Environment Interactions (EU-GEI) and Genetics and Psychosis (GAP) studies were included at FEP and were followed up 5 years later. One-factor (global negative symptoms), uncorrelated two-factor (DE-AA), and correlated two-factor structures were modelled using confirmatory factor analysis. Regression analyses were applied to examine the associations between these factors and negative symptom trajectories, functioning, and quality-of-life outcomes. Study Results The correlated two-factor model composed of DE and AA best fitted the data and exhibited 5-year stability. The regression model adjusted for AA accounted for more variance (59.2%) than global negative symptoms (52.8%) in explaining the enduring course of negative symptoms. Baseline AA was the only negative symptom factor that significantly predicted individuals’ functional outcome at follow-up (B=-1.76, p=0.037). All negative symptom dimensions negatively predicted employment status, whereas lower educational attainment was primarily related to AA severity at baseline. Conclusions Our findings support the validity and longitudinal stability of the two-dimensional (DE-AA) approach to negative symptoms in individuals with FEP. AA in particular exhibited distinctive predictive value, underscoring its potential clinical utility for early identification and the development of targeted interventions.