Pupillary light reflex in panic disorder. A trial using audiovisual stimulation.

Although many previous studies reported abnormalities of autonomic function in patients with panic disorder (PD), almost all targets in those studies primarily focused on cardiovascular autonomic functions. In the present study, we determined whether PD patients exhibited abnormalities in the pupillary autonomic nervous system (ANS). Before and after audiovisual stimulation (AS), which induced mental stress through exposure to video images of high stress experiences, such as driving motor vehicles, the pupillary light reflex (PLR) was measured by infrared pupillometer in 13 remitted PD patients and twenty age– and gender–matched normal controls (NC). Before and after AS, there were no significant differences in initial pupillary diameters in dark conditions (D1), pupillary diameters at maximum constriction (D2) or constriction ratios (CR: (D1-D2)/D1) between PD and NC subjects. However, the CR ratio (CR before/CR after) was significantly higher in the PD group than in the NC. These findings suggest that even remitted PD patients may have a dysfunctional PLR regulation with experimental stressors such as AS.