Blunted light exposure amplitudes in patients with opioid use disorder.

Accumulating evidence implicates sleep and circadian rhythm disruption in substance use disorders, including opioid use disorder (OUD). To understand whether weaker light exposure time cues are observed in patients with OUD, we compared the amplitudes of personal light exposure in patients with OUD (n = 73) and healthy controls (n = 49). Participants monitored personal light exposure and rest/activity via wrist-worn actigraphy for 1 week. We calculated light and physical activity amplitude for each day with non-orthogonal spectral analysis. Patients with OUD demonstrated significantly lower light exposure amplitudes and significantly higher physical activity amplitudes compared to healthy controls, suggesting lower light exposure amplitudes are not accounted for by sedentary behavior in patients with OUD. Blunted light exposure amplitudes, indicative of a weaker time cue to the circadian clock, characterize patients with OUD and may represent a novel target for improving sleep and circadian health in OUD.