Curtis AF, Miller MB, Rathinakumar H, et al. - Given the prevalence of opioid use and sleep disruption in fibromyalgia, researchers examined how opioid use/dosage is associated with polysomnographically assessed sleep in patients with fibromyalgia and insomnia (FMI). Further, they explored the moderating effects of age and pain. Ambulatory polysomnography and 14 daily diaries were completed by participants (N = 193, Mage = 51.7, SD = 11.8, range = 18-77) with FMI. They observed greater %stage 2 and lower %slow-wave sleep (%SWS) in correlation with opioid use. Among opioid users (n = 65, ∼3 years usage), they observed an interaction of opioid dose (measured in lowest recommended dosage) with age that predicted sleep onset latency (SOL) and sleep efficiency; specifically, higher dosage predicted longer SOL and lower sleep efficiency for older, but not middle-aged/younger adults. Further, they noted an interaction of opioid dose with pain to predict %SWS and arousal index. Specifically, individuals with lower pain had reduced %SWS and higher arousal index, individuals with higher pain had increased %SWS in relation to a higher dosage. Findings thereby suggest an increase in lighter sleep/reduction in deep sleep in patients with chronic widespread pain in correlation with opioid use. Older patients and patients with low pain showed exacerbate disruption in relation to higher doses.