What Keeps Night Owls Well During the Week? Sleep Onset Consistency as a Moderator Between Morningness-Eveningness...

A preference for eveningness - one's perception of being most alert later in the day - is associated with negative developmental outcomes in adolescence. Sleep onset consistency is protective against such outcomes. Toward a more nuanced understanding of relations between sleep-wake processes and adolescent development, we examined weeknight sleep onset consistency as a moderator of relations between eveningness and multiple indicators of development.

A sample of 272 high-school students (M_age = 17 years, SD = 9.12 months; n = 133 identified as female; 41% non-Hispanic Black/African-American, 59% non-Hispanic White/European-American) participated in a week of at-home sleep actigraphy assessment in 2017-2018. Adolescents reported their morningness - eveningness, internalizing symptoms (depression, anxiety), positive affect (optimism and subjective happiness), and physical health, and mothers reported on youths' behavior problems. Relations were examined between morningness - eveningness and each indicator of development; sleep onset consistency was examined as a moderator of these associations.

On average, adolescents with a preference for eveningness had higher levels of externalizing behaviors and internalizing symptoms and lower levels of positive affect and physical health compared to peers with a preference for morningness (Bs = -0.27*-0.12***). Each association was moderated by weeknight sleep onset consistency. Across all indicators of development, evening-preferring youth with more consistent weeknight sleep onset had 0.49-0.72 SD better outcomes on average than evening-preferring youth with less consistent weeknight sleep onset.

Falling asleep at roughly the same time each night can protect adolescent night owls from behavior problems and internalizing symptoms and can promote their positive affect and physical health.