Melatonin for mellowing out sleep disturbances related to ADHD Original paper

Sleep disturbances and disorders are common among children and adults with attention deficit hyperactivity disorder (ADHD). This is usually a consequence of a delayed circadian rhythm, in which the body’s sleep response to rising melatonin levels is slower than the average. Therapies for delayed sleep phase syndrome (DSPS) include sleep hygiene and chronotherapy with melatonin and/or bright light therapy, but few studies have tested the efficacy of these strategies in adults with ADHD.

In this three-week double-blind, randomized controlled trial, 46 adults with ADHD and DSPS received sleep education and were then assigned to one of three groups: 0.5 mg of melatonin per day, 0.5 mg of melatonin plus 30 minutes of 10,000 lux bright light therapy per day, or 0.5 mg of placebo. Dim-light melatonin onset (DLMO, a biomarker indicating the time when melatonin reaches a threshold of 3 pg/ml) was measured in saliva at baseline to determine each participant’s internal circadian rhythm. Melatonin or placebo was administered three hours before DLMO. This timing was advanced by one hour each week. The primary outcome was DLMO, and the secondary outcome was ADHD symptoms using the ADHD Rating Scale-IV. Outcomes were measured at baseline, end of treatment (week 3), and two weeks after treatment.

At baseline, 36 (77%) participants had a late DLMO and were included in the analysis for the primary outcome. At three weeks, both treatment groups advanced their DLMO by one to two hours relative to baseline, while no effect was noted in the placebo group. Researchers noted significant effects for both treatments compared to placebo, but no significant differences between the two treatments. ADHD symptom scores changed only in the melatonin treatment group, in which they decreased by an average of 14%. Two weeks after the treatment ended, DLMO and ADHD symptom scores were no longer different between either treatment groups or the placebo group, as all levels returned to baseline. Thus, low dose melatonin may be helpful for people with ADHD and delayed sleep phase syndrome.

The administration of melatonin three hours before DLMO during the first week, followed by a one-hour weekly shift was intended to maximize the efficacy of the treatment. Under laboratory conditions, melatonin had the strongest effects on shifting the circadian rhythm when taken three hours before DLMO.