Currently doing an ENT rotation and saw a 4 y/o boy yesterday with sx of poor concentration, inability to follow directions, and irritability who generally made life miserable for the rest of his family and at daycare. He was otherwise healthy, with normal birthweight and growth patterns until 6 months of age, when he inexplicably fell off the growth curve despite normal nutrition. His pediatrician, reluctant to diagnose him with ADHD, began inquiring about his sleep habits and found that he had not been a "good sleeper." Since this kid was too irrascible to cooperate with a sleep study, Mom sat up one night with a tape recorder near his pillow at home and discovered frequent apneic periods to the tune of 44 in an hour and extensive snoring. He did not display behaviors consistent with daytime sleepiness, interestingly. He'll have his tonsils and adenoids removed, which should improve his disposition. Not getting adequate REM sleep, when growth hormone is released, is most likely the reason for being small for his age, my ENT preceptor explained. A kid who is chronically sleep deprived could certainly behave like a kid with ADHD, or possibly like a kid who might otherwise be diagnosed with bipolar disorder. This particular ENT sees this situation from time-to-time and he said the difference in these kids and their behavior is quite dramatic once their tonsils and adenoids are removed, as one might imagine. Yet, I don't recall having been taught or considered the possibility of sleep apnea, obstructive or central, in the differential diagnosis of behavior disorders in kids. It is interesting to consider the possibility that there is a sub-population of kids (or adults for that matter) diagnosed with ADHD who have sleep apnea. Anybody else seen cases like this?