hypertrophy) would suggest the presence of obstructive sl eep apnea hypopnea. Obstruc-
tive sleep apnea hypopnea and attention-de ficit/hyperactivity disorder may commonly
co-occur, and there may be causal links between  them; therefore, risk factors such as en-
larged tonsils, obesity, or a family history of sleep apnea may help alert the clinician to
their co-occurrence.
Substance/medication-induced  insomnia or hypersomnia. Substance use and substance
withdrawal (including medications) can prod uce insomnia or hypersomnia. A careful his-
tory is usually sufficient to identify the relevant substa nce/medication, and follow-up
shows improvement of the sleep  distur bance after discontinuation of the substance/med-