Sleep alterations in pediatric bipolar disorder versus attention deficit disorder.

Bipolar disorder (BD) and attention deficit/hyperactivity disorder (ADHD) share numerous clinical features, which can make the differential diagnosis challenging. Studies conducted in adults suggest that patients with BD and ADHD have different sleep patterns. However, in pediatric populations, data on these potential differences are scant. The present preliminary study was conducted to identify potential differences in sleep alterations among youths diagnosed with BD or ADHD compared to healthy controls (HC). A total of 26 patients diagnosed with BD (n = 13) or ADHD (n = 13) were compared to 26 sex- and age-matched HC ([HCBD ], n = 13, and [HCADHD ], n = 13). All participants underwent polysomnography. The mean duration of stage N2 sleep was shorter in the BD group than in controls (HCBD ). The BD group also had higher (non-significant) REM density (REMd) scores than controls while mean REMd scores were lower in the ADHD group versus controls. Compared to the ADHD group, the BD group presented a shorter N2 stage, a longer first REM sleep duration (R1), and greater REMd. According to our findings, these three variables-N2 stage, REMd, and R1-appear to differentiate patients with BD from those with ADHD and from HC.