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Summary: Decision‐making has been shown to suffer when circadian preference is misaligned with time of assessment; however, little is known about how misalignment between sleep timing and the central circadian clock impacts decision‐making. This study captured naturally occurring variation in circadian alignment (i.e., alignment of sleep–wake timing with the central circadian clock) to examine if greater misalignment predicts worse decision‐making. Over the course of 2 weeks, 32 late adolescent drinkers (aged 18–22 years; 61% female; 69% White) continuously wore actigraphs and completed two overnight in‐laboratory visits (Thursday and Sunday) in which both dim‐light melatonin onset (DLMO) and behavioural decision‐making (risk taking, framing, and strategic reasoning tasks) were assessed. Sleep–wake timing was assessed by actigraphic midsleep from the 2 nights prior to each in‐laboratory visit. Alignment was operationalised as the phase angle (interval) between average DLMO and average midsleep. Multilevel modelling was used to predict performance on decision‐making tasks from circadian alignment during each in‐laboratory visit; non‐linear associations were also examined. Shorter DLMO‐midsleep phase angle predicted greater risk‐taking under conditions of potential loss (B = −0.11, p = 0.06), but less risk‐taking under conditions of potential reward (B = 0.14, p = 0.03) in a curvilinear fashion. Misalignment did not predict outcomes in the framing and strategic reasoning tasks. Findings suggest that shorter alignment in timing of sleep with the central circadian clock (e.g., phase‐delayed misalignment) may impact risky decision‐making, further extending accumulating evidence that sleep/circadian factors are tied to risk‐taking. Future studies will need to replicate findings and experimentally probe whether manipulating alignment influences decision‐making. [ABSTRACT FROM AUTHOR]

Increasing evidence implicates sleep/circadian factors in alcohol use; however, the role of such factors in alcohol craving has received scant attention. Prior research suggests a 24-hour rhythm in related processes (e.g., reward motivation), but more research directly investigating a rhythm in craving is needed. Moreover, prior evidence is ambiguous whether such a rhythm in alcohol craving may vary by sleep/circadian timing. To examine these possibilities, 36 late adolescents (18–22 years of age; 61% female) with regular alcohol use but without a current alcohol use disorder were recruited to complete smartphone reports of alcohol craving intensity six times a day for two weeks. During these two weeks, participants wore wrist actigraphs and completed two in-lab assessments (on Thursday and Sunday) of dim light melatonin onset (DLMO). Average actigraphically derived midpoint of sleep on weekends and average DLMO were used as indicators of sleep and circadian timing, respectively. Multilevel cosinor analysis revealed a 24-hour rhythm in alcohol craving. Findings across the sleep and circadian timing variables converged to suggest that sleep/circadian timing moderated the 24-hour rhythm in alcohol craving. Specifically, people with later sleep/circadian timing had later timing of peak alcohol craving. These findings add to the growing evidence of potential circadian influences on reward-related phenomena and suggest that greater consideration of sleep and circadian influences on alcohol craving may be useful for understanding alcohol use patterns and advancing related interventions. [ABSTRACT FROM AUTHOR]

Insufficient sleep is linked to increased stress and suboptimal self-control; however, no studies have examined stress as a reason for why sleep affects self-control. Moreover, it is unknown if there are individual differences that make people vulnerable to this dynamic. Daily diary entries from 212 university students across 30 days were used in a multilevel path model examining if stress explained how prior night sleep affected next-day self-control difficulties and exploring if individual differences in sleep duration, stress, or self-control qualified this effect. Increased stress partially mediated of the effect of reduced sleep duration on increased next-day self-control difficulty. Moreover, short sleep increased next-day stress more for individuals with higher typical stress. Daytime stress especially amplified self-control difficulty for individuals with shorter typical sleep duration. Findings implicate stress as a substantial factor in how sleep loss undermines self-control and identify individuals particularly susceptible to this effect. [ABSTRACT FROM AUTHOR]