Associations Between Blunted Pupillary Constriction and Dilation in Individuals with Schizophrenia: Evidence of a...

Unpacking the pathophysiological mechanisms of schizophrenia is necessary for advancing prediction, prevention, and treatment efforts. Mechanisms can be identified using easy-to-use and scalable clinical biomarkers, which reflect illness processes. Pupillometry is one such biomarker. Blunted dilation related to cognitive demand has been interpreted as a metric of diminished effort in schizophrenia, while blunted constriction to light has been interpreted as a metric of altered autonomic balance in schizophrenia. However, these 2 sets of findings may also reflect a common mechanism of schizophrenia. Therefore, this study aimed to explore the association between blunted cognitive dilation and blunted constriction to light to provide a parsimonious mechanism of autonomic and effort disturbances experienced by individuals with schizophrenia.

We assessed light-induced constriction and cognitive dilation during a double-step task in individuals with schizophrenia (n = 84) and demographically matched healthy controls (HC, n = 69), compared these metrics between groups, and computed their correlation within each group.

Replicating prior findings, dilation and constriction were blunted in schizophrenia relative to HC. Blunted constriction and dilation were positively correlated in schizophrenia but not HC (although the 2 correlations did not differ significantly).

Findings provide, for the first time, preliminary support of a common mechanism linking blunted pupil constriction to light and dilation to cognitive demands in schizophrenia. We propose that individuals with schizophrenia may exhibit impaired top-down modulation of autonomic control. Future studies are needed to validate this proposed mechanism.