0648 Retinal responsivity is associated with light and season-related cognitions in older adults with seasonal depression

Abstract Introduction Maladaptive cognitions associated with lower light availability in winter and the changing of the seasons are elevated in winter depression and are treatment targets in psychotherapy. Mechanisms underlying the development of SAD-specific cognitions may be related to seasonal variation in melanopsin-driven retinal responsivity to light. Prior work has shown reduced retinal responsivity to light during the winter in seasonal depression. We hypothesized maladaptive seasonal cognitions would be associated with reduced retinal responses to light. We also tested whether age moderated this relationship, hypothesizing that this learned association may only appear in older individuals who have experienced a greater number of seasonal depressive episodes. Methods Participants ages 19-65 (M=36.13, SD=12.81) with seasonal depression (n=37) and non-depressed controls (n=32) completed assessments in winter months (21st December to 21st March). Maladaptive seasonal cognitions were measured by the Seasonal Beliefs Questionnaire (SBQ). Melanopsin-driven retinal responsivity was assessed using the post illumination pupil response (PIPR). Net PIPR as a percent of baseline was averaged across the 10-30 seconds post-stimulus for use in analyses. Using multiple regression, we tested (1) if seasonal beliefs predict the PIPR and (2) if an interaction between seasonal beliefs and age predicts the PIPR, controlling for gender, the pupillary light reflex (PLR), and circadian time of testing from Dim Light Melatonin Onset. Results Seasonal beliefs were not associated with the PIPR (b= -0.86e-5, SE=0.27e-3, p=0.98). There was a significant interaction between seasonal beliefs and age on the PIPR (b= -0.56e-4, SE=0.23e-4, p=0.02), in which greater seasonal beliefs were associated with reduced PIPR in older individuals but not younger individuals. The Johnson-Neyman interval indicated that in participants above age 49, greater seasonal beliefs were significantly associated with lower retinal responsivity (PIPR; p< 0.05). Conclusion Greater seasonal beliefs were associated with reduced retinal responsivity, but only in older adults with seasonal depression. It is possible that reduced retinal responsivity creates learned maladaptive schemas regarding seasonal changes that are reinforced with annually recurring winter depressive episodes. However, longitudinal data focused on changes in seasonal beliefs resulting from reduced retinal sensitivity is necessary to test whether retinal responsivity is a mechanism in the formation of these seasonal-specific cognitions. Support (if any)