O013 Examining insomnia and delayed sleep–wake phase disorder during adolescenceora

Abstract Introduction Measuring circadian timing informs the diagnosis of Insomnia and Delayed Sleep–Wake Phase Disorder (DSWPD) in adults, however this has not been studied in adolescents. This study examined circadian timing of sleep in adolescents, including those meeting diagnostic criteria for insomnia and DSWPD. Methods Participants were a community sample of adolescents (n = 125, age M ± SD = 13.52 ± 1.04) who completed a diagnostic sleep interview (SCISD) to assess whether they met subthreshold or threshold insomnia or DSWPD criteria. Participants completed two weeks of sleep–wake monitoring during school term, with circadian phase measured via salivary dim light melatonin onset [DLMO] on the last Friday of sleep monitoring. Results Twenty (16%) adolescents met insomnia criteria (n = 7 threshold, n = 13 subthreshold), 14 (11.2%) DSWPD criteria (n = 9 threshold, n = 5 subthreshold), and 91 (72.8%) did not meet any criteria for either. In adolescents who met insomnia criteria, DLMO occurred at 20:57h ± 1.16 (range 18:56–00:00h), with sleep onset occurring 1.73h ± 1.31 after DLMO (range -1.78- 3.5h). In adolescents who met DSWPD criteria, DLMO occurred at 21:05 ± 1.12 (range 19:17–23:43h), with sleep onset occurring 2.38h ± 1.18 after DLMO (range 0.44-4.02h). For those who met no criteria for either condition, DLMO occurred at 20.60 ± 1.22 (range 18.02-23.68h), with sleep onset occurring 1.97 ± 1.22 after DLMO (range -1.54-5.67h). Twelve participants initiated sleep before or within 30 minutes of their DLMO time (n = 2 insomnia, n = 2 DSWPD, n = 8 no symptoms). Discussion We observed large inter-individual variability in circadian timing and phase angle in adolescents meeting diagnostic criteria for insomnia and DSWPD, indicating limited differentiation in circadian timing using diagnostic interviews.