Melatonin and sleep parameters in patients with chronic pain: first results from the double-blind randomised controlled trial of exogenous administration of melatonin in chronic pain (DREAM-CP) trial

Chronic pain is associated with sleep disturbance and melatonin may improve both sleep and pain.1 We undertook a double-blind randomised controlled crossover trial of melatonin in patients with non-cancer severe chronic pain.2 The trial was prospectively registered (ISRCTN12861060). After ethical approval, clinical trial authorisation, and written informed consent, 60 adult patients (age 31–79 yr, 36 female, 24 male), with an average pain intensity score of 7 or more were randomised, and 51 completed both treatment arms. Participants received either melatonin (Circadin™; Flynn Pharma, Stevenage, UK) 2 mg daily at night or placebo for 6 weeks, followed by a washout period, then a further 6 weeks of placebo or melatonin. The primary outcome measure was sleep disturbance measured using the Verran Snyder-Halpern (VSH) sleep scale