Associations between cardiorespiratory fitness, body mass index, and reward processing in first-episode schizophrenia

Motivational impairment is a core feature of schizophrenia that contributes to functional disability and reduced quality of life. Although reward-related event-related potentials (ERPs), including the stimulus-preceding negativity (SPN), reward positivity (RewP), and late positive potential (LPP), have been linked to motivational impairment, they have not been examined in relation to potentially modifiable physical health factors early in illness. This study tested associations between cardiorespiratory fitness, body mass index (BMI), and reward-related ERPs in individuals with first episode schizophrenia. Twenty-three participants (M age = 22.05 years; 78% male) completed standardized assessments of aerobic fitness and BMI and performed a monetary reward task during EEG recording. Higher BMI was significantly associated with reduced RewP amplitude, whereas no significant associations were found between cardiorespiratory fitness and ERP measures. These findings suggest that metabolic burden may be linked to early abnormalities in evaluative stages of reward processing in schizophrenia. The relationship between physical health and reward dysfunction is likely bi-directional, highlighting the need for longitudinal and intervention studies. ERPs may serve as mechanistic biomarkers for clarifying these pathways and identifying early intervention targets. • Elevated body mass index (BMI) is associated with blunted reward processing (RewP) in individuals with first-episode schizophrenia • No associations were observed between cardiorespiratory fitness and anticipatory (SPN) and later evaluative (LPP) stages of reward processing • Physical health is a modifiable treatment target for motivational impairment • ERPs may offer utility as neurophysiological biomarkers of treatment effects