Julia F. Dewald

A Cross-Cultural Comparison of Sleep Duration Between U.S. and Australian Adolescents The Effect of School Start Time, Parent-Set Bedtimes, and Extracurricular Load

STUDY OBJECTIVE To test whether sleep duration on school nights differs between adolescents in Australia and the United States and, if so, whether this difference is explained by cultural differences in school start time, parental involvement in setting bedtimes, and extracurricular commitments. PARTICIPANTS Three hundred eighty-five adolescents aged 13 to 18 years (M = 15.57, SD = 0.95; 60% male) from Australia and 302 adolescents aged 13 to 19 years (M = 16.03, SD = 1.19; 35% male) from the United States. METHODS Adolescents completed the School Sleep Habits Survey during class time, followed by an 8-day sleep diary. RESULTS After controlling for age and gender, Australian adolescents obtained an average of 47 minutes more sleep per school night than those in the United States. Australian adolescents were more likely to have a parent-set bedtime (17.5% vs. 6.8%), have a later school start time (8:32 a.m. vs. 7:45 a.m.), and spend less time per day on extracurricular commitments (1 h 37 min vs. 2 h 41 min) than their U.S. peers. The mediating factors of parent-set bedtimes, later school start times, and less time spent on extracurricular activities were significantly associated with more total sleep. CONCLUSIONS In addition to biological factors, extrinsic cultural factors significantly affect adolescent sleep. The present study highlights the importance of a cross-cultural, ecological approach and the impact of early school start times, lack of parental limit setting around bedtimes, and extracurricular load in limiting adolescent sleep.Study Objective. To test whether sleep duration on school nights differs between adolescents in Australia and the United States and, if so, whether this difference is explained by cultural differences in school start time, parental involvement in setting bedtimes, and extracurricular commitments. Participants. Three hundred eighty-five adolescents aged 13 to 18 years (M = 15.57, SD = 0.95; 60% male) from Australia and 302 adolescents aged 13 to 19 years (M = 16.03, SD = 1.19; 35% male) from the United States. Methods. Adolescents completed the School Sleep Habits Survey during class time, followed by an 8-day sleep diary. Results. After controlling for age and gender, Australian adolescents obtained an average of 47 minutes more sleep per school night than those in the United States. Australian adolescents were more likely to have a parent-set bedtime (17.5% vs. 6.8%), have a later school start time (8:32 a.m. vs. 7:45 a.m.), and spend less time per day on extracurricular commitments (1 h 37 min vs. 2 h 41 min) than their U.S. peers. The mediating factors of parent-set bedtimes, later school start times, and less time spent on extracurricular activities were significantly associated with more total sleep. Conclusions. In addition to biological factors, extrinsic cultural factors significantly affect adolescent sleep. The present study highlights the importance of a cross-cultural, ecological approach and the impact of early school start times, lack of parental limit setting around bedtimes, and extracurricular load in limiting adolescent sleep.

The Chronic Sleep Reduction Questionnaire (CSRQ): a cross-cultural comparison and validation in Dutch and Australian adolescents

Although adolescents often experience insufficient and/or poor sleep, sleep variables such as total sleep time do not account for individuals’ sleep need and sleep debt and may therefore be an inadequate representation of adolescents’ sleep problems and its daytime consequences. This problem can be overcome by using the Chronic Sleep Reduction Questionnaire (CSRQ), an assessment tool that measures symptoms of chronic sleep reduction and therefore accounting for sleep need and sleep debt. The present study aims at developing an English version of the CSRQ and assesses the reliability and validity of the Dutch and the English CSRQ version. The CSRQ was administered in large Dutch (n = 166, age = 15.2 ± 0.57 years, 28% male) and Australian (n = 236, age = 15.5 ± 0.99 years, 65% males) samples. Subjective sleep variables were measured with surveys and sleep diaries of five school nights. Additionally, sleep of the same five nights was monitored with actigraphy. Both CSRQ versions showed good psychometric properties concerning their reliability (Dutch: α = 0.85; English: α = 0.87) and validity as the same overall structure of the two CSRQ versions and significant correlations with subjective and objective sleep variables were found. School grades were related to chronic sleep reduction, whereas the relationship between grades and other sleep variables was weak or absent. These results highlight the idea that chronic sleep reduction may be a better indicator of adolescents’ insufficient and/or poor sleep than other sleep variables such as total sleep time.

The relationship between adolescents’chronic sleep reduction and objective sleep parameters during low and high stress periods

Objectives: The aim of this study was to move forward from: ‘‘snapshot’’ cognitive probe studies used to establish selective attention in insomnia and understand processing of salient sleep words over time within the context of approach and avoidance. Methods: The novel methodology to insomnia research, eye tracking, was used to monitor the eye movements of individuals with psychophysiological insomnia (PI) and good sleepers (GS) to sleep positive, sleep negative and neutral words over a three second period. Results: The data shows that individuals with insomnia are less accurate [F(1.39) = 4.6, P < .05], take longer to fixate on the target word [F(1.39) = 5.0, P < .05] and take longer to move from distractor to target word [F(1.39) = 3.9, P < .05]. There is a trend towards significance suggestive of faster processing of positive sleep words compared to sleep negative or neutral words [F(2.78) = 2.9, P = .07]. Conclusions: Irrespective of word salience, the PI would appear to show detrimental processing overall compared to GS. Interesting questions arise within this context of whether this is an artefact of fatigue or there is indeed a processing impairment. The trend toward faster processing of sleep positive words would suggest that there is a possible selective processing impairment.

The influence of real-world stress on adolescents’ sleep

Objectives: The aim of this study was to move forward from: ‘‘snapshot’’ cognitive probe studies used to establish selective attention in insomnia and understand processing of salient sleep words over time within the context of approach and avoidance. Methods: The novel methodology to insomnia research, eye tracking, was used to monitor the eye movements of individuals with psychophysiological insomnia (PI) and good sleepers (GS) to sleep positive, sleep negative and neutral words over a three second period. Results: The data shows that individuals with insomnia are less accurate [F(1.39) = 4.6, P < .05], take longer to fixate on the target word [F(1.39) = 5.0, P < .05] and take longer to move from distractor to target word [F(1.39) = 3.9, P < .05]. There is a trend towards significance suggestive of faster processing of positive sleep words compared to sleep negative or neutral words [F(2.78) = 2.9, P = .07]. Conclusions: Irrespective of word salience, the PI would appear to show detrimental processing overall compared to GS. Interesting questions arise within this context of whether this is an artefact of fatigue or there is indeed a processing impairment. The trend toward faster processing of sleep positive words would suggest that there is a possible selective processing impairment.