Testing biopsychosocial models integrating electrodermal activity, neurocognition, and social cognition to predict the functional outcomes among people with schizophrenia at three time points over 12 months

Background: Stress plays an important role in the etiology, progress, and prognosis of schizophrenia. Understanding how stress responsivity influences the functional outcomes among people with schizophrenia in a biopsychosocial context is important to improving interventions and reducing the heterogeneity of intervention outcomes. It is believed that psychophysiology, neurocognition, and social cognition are three significant predictors of the functional outcomes of schizophrenia; however, the patterns of the relationships among these factors and their combined predictive value are not clearly understood. This study had three aims: (1) identify the relationships among static skin conductance level (SCL), skin conductance stress reactivity (SCSR), neurocognition, emotional perception, and functional outcomes among people with schizophrenia;(2) compare three hierarchical biopsychosocial models (parallel, two-level, and three-level) integrating static SCL, SCSR, neurocognition, and emotional perception to predict the functional outcomes among people with schizophrenia at three points in time over 12 months; and (3) test the validity of the best biopsychosocial predictive model after controlling for psychiatric symptoms.;Methods: Participants were 103 people recruited upon admission to four highly similar psychosocial rehabilitation programs who were followed prospectively for 12 months. At 6 months, 90 subjects completed a follow-up functional outcome evaluation. At 12 months, 82 subjects completed a follow-up functional outcome and neuropsychological evaluation. Electrodermal activity (EDA) measures of resting arousal and stress reactivity were taken at baseline. Neurocognition at baseline was measured using working and secondary memory, vigilance, and speed of processing variables. Social cognition at baseline was measured using emotion perception tests. Role functioning in independent living, social, and work domains were measured with the Role Functioning Scale at baseline and 6 and 12 months. Structural equation modeling using EQS version 6.1 for Windows was used to test three biopsychosocial predictive models' change over time, both before and after controlling for overall psychiatric symptoms.;Results: A three-level hierarchical model combining EDA, neurocognition, and emotional perception was predictive of functional outcomes among people with schizophrenia at baseline (S-Bchi2 = 10.009, df = 9, p = .350, CFI = .986, SRMR = .052, RMSEA = .033), 6 months (S-Bchi2 = 0.923, df = 9, p = 1.000, CFI = 1.000, SRMR = .016, RMSEA = .000), and 12 months (S-Bchi2 = 3.874, df = 9, p = .920, CFI = 1.000, SRMR = .030, RMSEA = .000). Results indicated that higher EDA was positively related to better neurocognition; better neurocognition was related to higher level of emotional perception, and the model significantly predicted functional outcomes at each time point. The model remained statistically significant at all time points after controlling for baseline psychiatric symptoms.;Conclusion: The three-level hierarchical biopsychosocial model tested in this study showed robustness in predicting concurrent and 6- and 12-month prospective functional outcomes among people with schizophrenia. These results are interpreted to mean that higher levels of static SCL and SCSR represent an increased capacity to engage with environmental stimuli, which has been associated with better neurocognition and emotional perception, resulting in better functional outcomes before and after people with schizophrenia received rehabilitation services. This model remained significant after controlling for psychiatric symptoms. These findings have relevance for understanding schizophrenia functioning and psychosocial interventions for schizophrenia by illustrating the multilevel biopsychosocial factors that predict functional outcomes.