O069 At home lighting intervention as an adjunct to antidepressant treatment: A pilot study

Abstract Evening light exposure is disruptive to sleep and circadian rhythms. This disruption may be amplified for people taking Selective-Serotonin Reuptake Inhibitors (SSRIs), as SSRIs increase sensitivity to the non-visual effects of light. Minimising the amount of evening light exposure may therefore improve antidepressant treatment responses by minimising disruption and improving sleep and mood. We investigated the potential of a home-lighting intervention focused on minimising evening light to reduce depressive symptoms in individuals taking an SSRI. Individuals taking an SSRI who reported moderate or high levels of depressive symptoms, assessed via the Beck Depression Inventory, were recruited (N=24). After completing a baseline week of at-home monitoring of sleep, light, and mood, participants were randomly allocated to four weeks of a smart light intervention (n=12) or a control condition (n=11). Participants in the light intervention group were asked to replace their existing evening lighting with dimmed/warm smart lights. There was no difference in depressive symptoms between groups during the baseline week. Following the intervention period, participants in the intervention group reported significantly reduced depressive symptoms compared to those in the control group, with a large effect (d=2.11) and an average shift from severe to mild depressive symptoms. The intervention group showed a significant reduction in evening light following the intervention, averaging a 21 lux difference in change scores compared to the control group (d=1.11). We conclude that at-home light interventions that reduce evening light exposure hold promise as an adjunctive treatment for individuals experiencing depression while taking SSRIs.