Abstract
Schizophrenia (SZ) is associated with impaired adaptive functioning, including difficulties managing the demands of independent living, work, school, and interpersonal relationships. Prior studies have linked the physiological stress response with less effective coping in daily life. Differences in stress-response tendencies may also support heterogeneity in daily functioning in SZ. The present study examined two established measures of the stress response in patients with first-episode SZ. Salivary cortisol was included as an index of hypothalamic-pituitary-adrenal response. Vagal suppression (VS), a measure of stress-related reduction in heart rate variability, was used to assess parasympathetic flexibility. Greater cortisol response and VS to social-evaluative stress were predicted to be associated with better functioning in SZ over and above relationships with social cognition and neurocognition, two well-established predictors of functional outcome. Thirty-eight first-episode SZ outpatients and 29 healthy comparison subjects (HC) provided social cognitive, neurocognitive, and physiological measurements before and after the Trier Social Stress Test (TSST). Although SZ and HC did not differ on VS to the TSST, patients exhibited significant associations between VS and functioning across all four domains of the Role Functioning Scale. Furthermore, greater VS predicted more effective functioning with friends, beyond the contributions associated with social cognition and neurocognition, and strengthened the positive effects of higher levels of social cognition on independent living/self-care. VS elicited by social-evaluative stress in the laboratory may reflect stress-response tendencies in daily life that are relevant for daily functioning in first-episode SZ.