[The use of social media modifies teenagers' sleep-related behavior].

Modification of sleep behaviors in teenagers has been observed over the past 30years with a reduction in overall sleep time and an increasing number of teenagers suffering from sleep deprivation. Sleep deprivation is linked to physical problems such as obesity but also to change in performance at school and mood disorders. Changes have been associated with the use of screens, cell phones, Internet and social media. Use of screens has been shown to delay sleep onset and melatonin secretion and stimulation of wake systems by interaction with social media may exacerbate these effects. The links between the use of social media and sleep patterns have not been fully explored. Our study aimed to evaluate the effects of social media on teenagers' sleep and the impact of sleep deprivation. As part of a sleep education program conducted in middle schools, teenagers from 6th to 9th grade were invited to complete an online questionnaire on sleep habits with teacher supervision and after parental consent. Outcome measures were sleep and wake times with estimated sleep duration in school (SP) and rest periods (RP), use of screens (computers, tablets, smartphones and video game consoles), the use of social media and impact on visual analogue scales of sleep quality, mood and daytime functioning. Students were divided into those with clear sleep deprivation (sleep time<6hours in SP) and those whose sleep time was in line with the National Sleep Foundations recommended sleep needs for teenagers (9hours or more). A total of 786 questionnaires were completed and 776 were exploitable. Four schools took part with 408/786 girls (64.2 %) and a mean age of 12.4±1.24. Internet access was almost universal (98.3 %), 85.2 % had cell phones and 42.7 % had a personal computer in their bedroom. Social media was used by 64.6 %. After dinner, 52.6 % spent more than an hour and 14.7 % spent more than 2hours in front of a screen. After bedtime, 51.7 % regularly used electronic devices of which 25.6 % had a screen-based activity (e.g. texts, social media, video games or television). During the night, some teens woke up to continue screen-based activities: 6.1 % in order to play online video games, 15.3 % to send texts and 11 % to use social media. Bedtimes were later in PR compared with PS (22h06±132 vs. 23h54±02; P<0.0001) as were wake times (7h06±36 vs. 10h06±102; P<0.0001). Sleep time was clearly longer in PR (10h12±126 P<0.0001) compared to PS. For students in 6th grade compared to 9th grade in sleep duration in SP decreased (8:55±90 vs. 7:25±93; P<0.0001), whereas sleep duration during RP was stable (10h08±118 vs. 10h08±90 P<0.029). No significant difference was found between girls and boys for sleep duration, sleep quality, performance during the day or mood. Sleep deprivation during the week (6hours or less) was less common in 6th graders 5 % vs. 15 % (P<0.0001). In sleep deprived teens compared to teens sleeping, the recommended ≥9hours, difficulties falling asleep were reported with 33 % vs. 9 % taking over an hour to fall asleep (P<0.0001) and difficulties getting up in the morning were more common (7.05±3.27 vs. 5.74±2.97; P=0.0003). Sleep deprivation had an effect on daytime performance: teenagers deprived of sleep were more likely to report a need to fight sleepiness, (5.93±3.24 vs. 2.84±2.44 P<0.0001) and had reduced energy during the day (6.21±2.86 vs. 7.77±2.07 P<0.0001). A negative effect on mood was evident: in sleep, deprived teenagers irritability (5.28±3.12 vs. 3.30±2.34; P<0.0001) and feelings of sadness (3.97±2.99 vs. 2.59±2.15; P=0.003) were more common. There was a clear association between sleep deprivation and access to screens and social media: sleep deprived teens were at more risk of nocturnal disruption with a higher prevalence of computers (67 % vs. 33 %; P<0.0001), cell phones (99 % vs. 80 %; P=0.0001) and smart phones (85 % vs. 66 %; P=0.0001) in their bedrooms. Access to social media and especially a cell phone in teenagers' bedrooms is associated with a reduction in sleep time during the school week with negative effects on daily functioning and mood which increases with increasing age. Education about use of social media and sleep for teenagers needs to start early as modifications in sleep and evening use of screens was present on our population from 11years on and to involve parents as setting parent controlled bedtimes has been shown to increase teenage sleep time.

Royant-Parola S ，Londe V ，Tréhout S ，Hartley S ... -  《ENCEPHALE-REVUE DE PSYCHIATRIE CLINIQUE BIOLOGIQUE ET THERAPEUTIQUE》

[Mass media consumption in adolescence].

Bercedo Sanz A ，Redondo Figuero C ，Pelayo Alonso R ，Gómez Del Río Z ，Hernández Herrero M ，Cadenas González N ... -  《ANALES DE PEDIATRIA》

Age-related changes in sleep/wake patterns among Korean teenagers.

Yang CK ，Kim JK ，Patel SR ，Lee JH ... -  《-》

Disruption of adolescents' circadian clock: The vicious circle of media use, exposure to light at night, sleep loss and risk behaviors.

Although sleep is a key element in adolescent development, teens are spending increasing amounts of time online with health risks related to excessive use of electronic media (computers, smartphones, tablets, consoles…) negatively associated with daytime functioning and sleep outcomes. Adolescent sleep becomes irregular, shortened and delayed in relation with later sleep onset and early waking time due to early school starting times on weekdays which results in rhythm desynchronization and sleep loss. In addition, exposure of adolescents to the numerous electronic devices prior to bedtime has become a great concern because LEDs emit much more blue light than white incandescent bulbs and compact fluorescent bulbs and have therefore a greater impact on the biological clock. A large number of adolescents move to evening chronotype and experience a misalignment between biological and social rhythms which, added to sleep loss, results in e.g. fatigue, daytime sleepiness, behavioral problems and poor academic achievement. This paper on adolescent circadian disruption will review the sensitivity of adolescents to light including LEDs with the effects on the circadian system, the crosstalk between the clock and the pineal gland, the role of melatonin, and the behavior of some adolescents(media use, alcohol consumption, binge drinking, smoking habits, stimulant use…). Lastly, some practical recommendations and perspectives are put forward. The permanent social jet lag resulting in clock misalignment experienced by a number of adolescents should be considered as a matter of public health.

Touitou Y ，Touitou D ，Reinberg A 《-》

Featured Article: Technology Use and Sleep in Adolescents With and Without Attention-Deficit/Hyperactivity Disorder.

This study used a multi-informant approach to examine differences in types and rates of technology used by adolescents with and without attention-deficit/hyperactivity disorder (ADHD), associations between technology use and sleep/daytime sleepiness, and whether technology use was differentially related to sleep/daytime sleepiness in adolescents with and without ADHD. Eighth graders with (n = 162) and without (n = 140) ADHD were recruited. Adolescents completed questionnaires assessing time spent using technology, sleep-wake problems, school-night time in bed, and daytime sleepiness. Parents and teachers reported on adolescents' technology use and daytime sleepiness, respectively. Adolescents with ADHD had significantly greater total technology, television/movie viewing, video game, and phone/video chatting use than adolescents without ADHD. Adolescents with ADHD engaged in twice as much daily video game use compared to those without ADHD (61 vs. 31 min). Controlling for medication use, ADHD status, pubertal development, sex, and internalizing symptoms, greater parent- and adolescent-reported technology use was associated with more sleep-wake problems and less time in bed. ADHD status did not moderate the relations between technology use and these sleep parameters. In contrast, ADHD status moderated the association between parent-reported technology use and teacher-reported daytime sleepiness, such that this association was significant only for adolescents with ADHD. Technology use, although more prevalent in adolescents with ADHD, is linked with more sleep problems and reduced school-night sleep duration regardless of ADHD status. Technology use is associated with teacher-rated daytime sleepiness only in adolescents with ADHD. Clinicians should consider technology usage when assessing and treating sleep problems.

Bourchtein E ，Langberg JM ，Cusick CN ，Breaux RP ，Smith ZR ，Becker SP ... -  《-》