Cross-sectional and prospective analysis of the association of the pupillary light reflex with suicidal ideation and suicide attempts.

Predictive models of near-term suicidal behavior are not powerful and have low positive predictive value. A prior small pilot study showed a relationship between suicidal ideation (SI) or suicide attempts (SA) with rapid averaged maximum constriction velocities (aMCV) obtained during assays of the pupillary light reflex. The present report aims to replicate these findings in a larger cross-sectional study of patients with anxious and depressive symptoms and then examine the optimal value of MCV in prospective identification of near-term events which represent high risk for SA. The cross-sectional analysis revealed that aMCV was not associated with SI, but a rapid aMCV was associated with multiple SA. Adding severity of anxiety symptoms along with aMCV further improved the cross-sectional model of multiple SA. We utilized an optimized value of aMCV (≥4.4 mm/s) obtained from the cross-sectional study and examined its association with prospective near-term events of high suicide risk and found this value of aMCV produced a sensitivity of 80% and positive predictive value (PPV) of 26.6% but an aMCV value of 6 mm/s yielded a sensitivity of 60% and PPV of 50%. This PPV may be clinically useful in high stakes such as near-term suicidal crisis events. Further study of this topic is justified with larger samples, with the goal of developing a point of care biomarker to supplement traditional demographic and clinical factors associated with near-term crisis suicidal events.