title: Sleep patterns in children with attention-deficit/hyperactivity disorder, tic disorder, and comorbidity.
abstract: BACKGROUND
  In children, attention-deficit/hyperactivity disorder (ADHD), tic disorder (TD), and their coexistence (ADHD + TD comorbidity) are very common and clinically important. Associated sleep patterns and their clinical role are still insufficiently investigated. This study aimed at characterizing these sleep patterns in children with ADHD, TD, and ADHD + TD comorbidity and determining whether, in ADHD + TD, the factors ADHD and TD may affect the sleep pattern in an independent (additive) or in a complex (interactive) manner.
  
  
  METHODS
  By means of polysomnography, sleep patterns were investigated in 4 groups of unmedicated 8.0-16.4-year-old children (healthy controls, ADHD-only, TD-only, and ADHD + TD). Each group consisted of 18 subjects matched for age, gender, and intelligence.
  
  
  RESULTS
  ADHD was primarily characterized by increase in rapid eye movement (REM) sleep, whereas TD patients displayed lower sleep efficiency and elevated arousal index in sleep. In children with ADHD + TD, both effects appeared. No interaction between the ADHD and TD factors was found for any of the sleep parameters. Significant correlations between sleep patterns and clinical symptoms were found.
  
  
  CONCLUSIONS
  ADHD and TD are characterized by specific sleep alterations. When coexisting, the two disorders alter the sleep pattern in an additive manner, suggesting a high impact on clinical and therapeutic perspectives.
authors.affiliation: Institute of Physiology, Bulgarian Academy of Sciences, Sofia, Bulgaria.
authors.forename: Roumen
authors.initials: R
authors.lastname: Kirov
authors.forename: Joerg
authors.initials: J
authors.lastname: Kinkelbur
authors.forename: Tobias
authors.initials: T
authors.lastname: Banaschewski
authors.forename: Aribert
authors.initials: A
authors.lastname: Rothenberger
mesh_terms: D000293:Adolescent; D001289:Attention Deficit Disorder with Hyperactivity / Q000175:diagnosis* / Q000453:epidemiology; D002648:Child; D002653:Child Behavior Disorders / Q000175:diagnosis / Q000453:epidemiology; D015897:Comorbidity; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007389:Internal-External Control; D008297:Male; D010552:Personality Assessment; D017286:Polysomnography; D012894:Sleep Stages; D012893:Sleep Wake Disorders / Q000175:diagnosis* / Q000453:epidemiology; D013981:Tic Disorders / Q000175:diagnosis* / Q000453:epidemiology; D005879:Tourette Syndrome / Q000175:diagnosis / Q000453:epidemiology