Longitudinal relationships between mismatch negativity, cognitive performance, and real-world functioning in early psychosis.

BACKGROUND

Reduced mismatch negativity (MMN) is observed in early psychosis (EP) and correlated with cognition and functioning, but few studies have examined their longitudinal relationships and diagnostic specificity. We examined MMN, neuro- and social-cognition, and functional measures in EP patients with schizophrenia-spectrum (SZ) or bipolar disorder (BD) over a 1-year follow-up.

METHODS

54 EP patients (SZ: n = 24; BD: n = 30) and 42 healthy controls completed baseline measures: MMN, neuro- and social-cognition, and functional assessments. 30 EP patients completed 12-month follow-up assessments. Patients and controls were compared on MMN at baseline and follow-up, and diagnostic subgroup analyses were performed. Associations amongst MMN, neuro- and social cognition, and clinical measures were examined and predictive models of follow-up outcomes were conducted.

RESULTS

EP patients showed significantly reduced MMN compared to controls at baseline (p = 0.023). MMN was impaired in SZ patients at baseline (p = 0.017) and follow-up (p = 0.003); BD patients did not differ from controls at either timepoint. MMN was associated with symptom severity and functioning at baseline, and with social cognition and functioning at follow up, but was not predictive of functional outcomes at follow-up.

CONCLUSIONS

MMN abnormalities were evident in EP SZ-spectrum disorders at both timepoints, but not in BD at either timepoint. MMN was associated with functioning cross-sectionally, but did not predict future functional outcomes. However, deficits in MMN were associated with social cognition, which may have downstream effects on community functioning. Implications for targeted interventions to improve social processing and community outcomes are discussed.