Parental perceptions of sleep patterns in children presenting at an ADHD clinic in Washington, DC, were assessed prospectively over a 6-month period. Of 108 children diagnosed with ADHD, 46 were taking stimulant medications. Parents of all ADHD patients, 35 controls with psychiatric disorders attending the same clinic, and 84 general pediatric outpatients were given a Sleep Behavior questionnaire, the Achenbach Child Behavior Checklist, and a medical history questionnaire.
Moderate to severe sleep disorders occurred in 22% of ADHD children, 10% of psychiatric controls, and 6% of pediatric controls (p<0.05). Among ADHD children, insomnia was increased three-fold in patients receiving stimulant therapy. In addition to insomnia, ADHD patients had daytime tiredness, decreased sleep requirement, and frequent awakenings, not associated with parasomnias, enuresis, or respiratory disturbances. 
COMMENT. Sleep disorders are more common in ADHD children than in other pediatric patients, and are more prevalent and severe in patients treated with stimulant medications. Questions regarding sleep habits are important in the initial and follow-up examinations of children with ADHD. The substitution of an antihypertensive agent, clonidine or Tenex, may be advisable when insomnia is severe. A combination of stimulant and clonidine is not generally advised, because of reported cardiac complications and rare fatalities. See Ped Neur Briefs May 1999;13:40, for a debate regarding methylphenidate and clonidine combination therapy.