Yamaguchi M, Yamada K, Iseki M, et al. - As patients with chronic pain frequently experience insomnia, researchers here examined if and how insomnia in chronic pain patients affect family caregiver burden. In this cross-sectional study, 60 patients with chronic pain of ≥ 3 months duration were assessed using the Athens Insomnia Scale (AIS), the Pain Disability Assessment Scale, the Hospital Anxiety and Depression Scale, and a pain intensity numerical rating scale. Zarit Burden Interview (ZBI) was performed of family members who accompanied chronic pain patients to hospital. Observations revealed independent association of insomnia with ZBI scores. Significant association of scores on the AIS subscale of physical and mental functioning during the day with ZBI scores was also evident. Based on these findings, they conclude that comorbid insomnia and physical and mental daytime functioning in chronic pain patients are linked with family caregiver burden; pain duration, pain-related disability, and pain intensity did not affect this link.