Adolescents who prefer to sleep and wake up later (“night owls”) reported greater impulsivity than those who prefer to sleep and wake up earlier (“morning larks”), according to a study at Sleep 2025.
Results show that adolescents with self-reported evening preference, or “night owl” tendencies, reported greater negative urgency and lack of perseverance, which are two aspects of impulsivity. This means that they were more likely to act impulsively when experiencing negative emotions and quit difficult tasks. In contrast, there was no association between objectively measured circadian phase and impulsivity.
RT’s Three Key Takeaways
- Evening Preference Linked to Impulsivity: Adolescents who identify as “night owls” reported higher levels of impulsivity, particularly negative urgency and lack of perseverance.
- Self-Reported vs. Biological Measures: No link was found between biologically measured circadian phase and impulsivity, suggesting psychological or behavioral influences on self-reported sleep preferences.
- Implications for Prevention: The findings support using sleep and circadian-based interventions during adolescence to reduce impulsivity-related risks like substance use.
“Surprisingly, we did not find a significant link between dim light melatonin onset and impulsivity in our sample,” said lead author Riya Mirchandaney, who is a doctoral candidate in clinical-health psychology at the University of Pittsburgh. “This suggests that there may be unmeasured psychological or behavioral factors influencing both impulsivity and the self-assessment of circadian preference, regardless of the timing of an individual’s internal circadian clock.”
According to the American Academy of Sleep Medicine, circadian rhythms are internal biological rhythms that exist in all living organisms. This timekeeping system, or “body clock,” is synchronized to the 24-hour, light–dark cycle. Circadian preference reflects an individual’s desired timing of sleep and wake, and circadian timing can be objectively measured by analyzing saliva or blood plasma to detect dim light melatonin onset.
The study involved 210 adolescents across two studies. They had a mean age of 17 years, and 60.5 percent were female. Participants completed self-reported measures of impulsivity and circadian preference. Laboratory samples of saliva were taken to assess circadian phase by determining dim light melatonin onset. During a week-long protocol, participants also wore a wrist actigraph to estimate sleep midpoint and duration, and at bedtime they completed an assessment of impulsivity.
Mirchandaney emphasized that the results could influence future research to help teens avoid the negative effects of impulsivity, which is a well-established contributor to alcohol and substance use.
“Adolescence may be a prime opportunity for preventing adverse outcomes associated with impulsivity using chronotherapeutic interventions to advance sleep and circadian timing,” she said.
