Chicken or the egg: The relationship between cognitive deficits and negative symptoms in first episode psychosis

BACKGROUND: Cognitive impairments and negative symptoms (NS) represent an unmet therapeutic need in psychotic disorders. Both NS and cognitive impairments, are key predictors of functioning. Both also appear during the illness prodrome, highlighting their relevance to the etiology of psychosis. Cross-sectional and longitudinal links between NS and cognition have been established, suggesting a common underlying foundation. Thus, investigating the relationship between cognition and NS is particularly relevant, especially given the clinical fluctuations seen in the early stages of psychosis and the marked cognitive deficits present throughout the illness. OBJECTIVE: The following study aims to investigate the longitudinal relationship between NS and cognition and whether, over the first two years following psychosis onset, 1) NS influences cognition, 2) cognition influences NS, or 3) the relationship is bidirectional. METHODS: We used data from the Recovery After an Initial Schizophrenia Episode Early Treatment Program (2010-2014). Participants underwent early treatment intervention, with assessments at baseline, 12, and 24 months using the Brief Assessment of Cognition in Schizophrenia and the Positive and Negative Syndrome Scale (n = 404). Random intercept cross-lagged panel models, which consider the temporal sequence of effects, were created to model the relationship between cognition and NS through the three timepoints over two years. RESULTS: We found a unidirectional relationship- declines in cognitive function predicted increased NS severity, while NS did not predict future cognitive function. CONCLUSION: This suggests that cognitive deficits may contribute to the development or exacerbation of NS. These findings underscore the role of cognition on NS trajectories and open new avenues for early psychosis treatments.