Sleep and alertness in children with ADHD

Objective: To evaluate sleep and alertness and to investigate the presence of possible underlying sleep/wake disorders in children with attention-defi cit/hyperactivity disorder (ADHD). Method: After 3 nights of adaptation in a room reserved for sleep studies in the department of child psychiatry, ch ildren underwent polysomnography (PSG) followed by the Multiple Sleep Laten cy Test (MSLT) and reaction time tests (RT) during the daytime. Thirty boys diagnosed as having ADHD (DSM-IV), aged between 5 and 10 years, and 22 age and sex-matched controls participated in the study. All children were medi cation-free and showed no clinical signs of sleep and alertness problems. R esults: No significant differences in sleep variables were found between bo ys with ADHD and controls. The mean latency period was shorter in children with ADHD. Significant differences were found for MSLT 1, 2 and 3 (p < .05) . Mean reaction time was longer in children with ADHD, with significant dif ferences in all tests (p < .05). Number and duration of sleep onsets measur ed by the MSLT correlated significantly with the hyperactivity-impulsivity and inattentive-passivity indices of the CTRS and CPRS. Conclusion: Childre n with ADHD were more sleepy during the day, as shown by the MSLT, and they had longer reaction times. These differences are not due to alteration in the quality of nocturnal sleep. The number of daytime sleep onsets and the rapidity of sleep-onsets measured as MSLT were found to be pertinent physio logical indices to discriminate between ADHD subtypes. These results sugges t that children with ADHD have a deficit in alertness. Whether this deficit is primary or not requires further studies.