Autonomic nervous system activation during social cognition tasks in patients with schizophrenia and their unaffected relatives

Abstract

Objective: To determine if patients with schizophrenia and their unaffected first degree relatives have abnormal autonomic nervous system (ANS) responses to social cognition tasks. Background: Social cognition impairments are significant in schizophrenia. ANS activity has been shown to be abnormal in schizophrenia patients, and some of these abnormalities seem to be shared by unaffected relatives of afflicted persons. Method: Heart rate variability (HRV) was measured at rest, and while performing social cognition tasks in patients with schizophrenia, their nonpsychotic firstdegree relatives, and matched healthy persons (n=19 in each group). Results: Social cognition tasks induced a shortening of the RR interval in unaffected relatives, but not in patients. Social cognition tasks generated decreases in high-frequency (HF, indicative of cardiac vagal activity) and in low frequency (LF, reflecting predominantly sympathetic activity) HRV in patients, while in relatives the decrease occurred in The HF component only. LF-HRV was higher in patients during a theory of mind task compared with a control task. These changes were not observed in healthy persons. Conclusions: Social cognitive tasks induce a pattern of peripheral autonomic activity different from that seen in generic arousal responses, and such pattern is abnormal in schizophrenia patients. Autonomic abnormalities in unaffected first degree relatives seem restricted to the parasympathetic division of the ANS.