Impact of methylphenidate on sleep problems in adults with ADHD: a pilot polysomnography study.

Background: Attention-deficit hyperactivity disorder (ADHD) is associated with disrupted sleep and circadian rhythm. Medication for ADHD may have side effects aggravating sleep-disturbances, however beneficial effects on ADHD may contribute to improve sleep.
Aims: This pilot study aims to examine outcomes of first time stimulant treatment on objective and subjective sleep characteristics, and psychiatric symptoms, in adult ADHD patients with pretreatment sleep problems, but without any primary sleep disorder.
Methods: In total, 9 previously unmedicated adult ADHD subjects who reported pretreatment sleep problems, completed polysomnography (PSG) and questionnaires on subjective sleep disturbances and psychiatric symptoms. Data was collected before and after 6 weeks on first time medication with immediate-release methylphenidate (MPH-IR), mean daily dose 43 mg.
Results: Subjects on-medication showed an increased percentage of Stage 2 sleep compared to their non-treated baseline (46.6% versus 55.2%, p  = .011). Otherwise, there were no significant changes in PSG variables. There were no firm changes in daytime sleepiness or symptoms of sleep disturbances.
Conclusions: These findings should be interpreted cautiously given the open-label design and small sample size, and should be examined in larger studies with more rigorous study designs.