***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: Study Objectives Published experimental sleep manipulation protocol s for adolescents have been limited to the summer , limiting causal conclusions about how short sleep affects them on school nights , when they are most likely to restrict their sleep . This study assesses the feasibility and emotional impact of a school-night sleep manipulation protocol to test the effects of lengthening sleep in habitually short-sleeping adolescents . Methods High school students aged 14 - 18 years who habitually slept 5 - 7 hours on school nights participated in a 5-week experimental sleep manipulation protocol . Participants completed a baseline week followed in r and omized counterbalanced order by two experimental conditions lasting 2 weeks each : prescribed habitual sleep ( HAB ; sleep time set to match baseline ) and sleep extension ( EXT ; 1.5-hour increase in time in bed from HAB ) . All sleep was obtained at home , monitored with actigraphy . Data on adherence , protocol acceptability , mood and behavior were collected at the end of each condition . Results Seventy-six adolescents enrolled in the study , with 54 retained through all 5 weeks . Compared to HAB , during EXT , participants averaged an additional 72.6 minutes/night of sleep ( p < .001 ) and had reduced symptoms of sleepiness , anger , vigor , fatigue , and confusion ( p < .05 ) . The large majority of parents ( 98 % ) and adolescents ( 100 % ) said they would " maybe " or " definitely " recommend the study to another family . Conclusions An experimental , school-night sleep manipulation protocol can be feasibly implemented which directly tests the potential protective effects of lengthening sleep . Many short-sleeping adolescents would benefit emotionally from sleeping longer , supporting public health efforts to promote adolescent sleep on school nights STUDY OBJECTIVES To examine the prospect i ve , reciprocal association between sleep deprivation and  depression among adolescents . DESIGN A community-based two-wave cohort study . SETTING A metropolitan area with a population of over 4 million . PARTICIPANTS 4,175 youths 11 - 17 at baseline , and 3,134 of these followed up a year later .  MEASUREMENTS Depression is measured using both symptoms of depression and DSM-IV major depression . Sleep deprivation is defined as ≤ 6 h of sleep per night . RESULTS Sleep deprivation  at baseline predicted both measures of depression at follow-up , controlling for depression at baseline . Examining the reciprocal association , major depression at baseline , but not symptoms predicted sleep deprivation at follow-up . CONCLUSION These results are the first to document reciprocal effects for major depression and sleep deprivation among adolescents using prospect i ve data . The data suggest reduced quantity of sleep increases risk for major depression , which in turn increases risk for decreased sleep BACKGROUND The relationship between inadequate sleep and mood has been well-established in adults and is supported primarily by correlational data in younger population s. Given that adolescents often experience shortened sleep on school nights , we sought to better underst and the effect of experimentally induced chronic sleep restriction on adolescents ' mood and mood regulation . METHODS Fifty healthy adolescents , ages 14 - 17 , completed a 3-week sleep manipulation protocol involving a baseline week , followed by a sleep restriction ( SR ) condition ( 6.5 hr in bed per night for five nights ) and healthy sleep duration ( HS ) condition ( 10 hr in bed per night for five nights ) . The study used a r and omized , counterbalanced , crossover experimental design . Participants ' sleep was monitored at home via self-report and actigraphy . At the end of each condition , participants and their parents completed question naires of mood and mood regulation . To assess for expectancy effects , we also analyzed parent and teen ratings of hyperactivity/impulsivity , which prior research suggests is not sensitive to SR in adolescents . Wilcoxon Signed Rank tests compared question naire outcomes across the two conditions . RESULTS Participants averaged 2.5 more hours of sleep per night during HS relative to SR . Compared with HS , adolescents rated themselves as significantly more tense/anxious , angry/hostile , confused , and fatigued , and as less vigorous ( p = .001-.01 ) during SR . Parents and adolescents also reported greater oppositionality/irritability and poorer emotional regulation during SR compared with HS ( p < .05 ) . There were no cross-condition differences in depression or hyperactivity/impulsivity ( p > .05 ) . CONCLUSIONS Findings complement prior correlational study results to show that after only a few days of shortened sleep , at a level of severity that is experienced regularly by millions of adolescents on school nights , adolescents have worsened mood and decreased ability to regulate negative emotions STUDY OBJECTIVES To investigate sleep EEG changes in adolescents across 7 nights of sleep restriction  to 5 h time in bed [ TIB ] ) and 3 recovery nights of 9 h TIB . METHODS A parallel-group design , quasi-laboratory study was conducted in a boarding school . Fifty-five healthy adolescents ( 25 males , age = 15 - 19 y ) who reported habitual TIBs of approximately 6 h on week nights ( group average ) but extended their sleep on weekends were r and omly assigned to Sleep Restriction ( SR ) or Control groups .  Participants underwent a 2-week protocol comprising 3 baseline nights ( TIB = 9 h ) , 7 nights of sleep opportunity manipulation ( TIB = 5 h for the SR and 9 h for the Control group ) , and 3 nights of recovery sleep ( TIB = 9 h ) .  Polysomnography  was obtained on two baseline , three manipulation , and two recovery nights . RESULTS Across the sleep restriction nights , total SWS duration was preserved relative to the 9 h baseline sleep opportunity , while other sleep stages were reduced . Considering only the first 5 h of sleep opportunity , SR participants had reduced N1 duration and wake after sleep onset ( WASO ) , and increased total sleep time ( TST ) , rapid eye movement ( REM ) sleep , and slow wave sleep ( SWS ) relative to baseline . Total REM sleep , N2 , and TST duration remained above baseline levels by the third recovery sleep episode . CONCLUSIONS In spite of preservation of SWS duration over multiple nights of sleep restriction , adolescents accustomed to curtailing nocturnal sleep on school day nights evidence residual effects on sleep macro-structure , even after three nights of recovery sleep . Older teenagers may not be as resilient to successive nights of sleep restriction as is commonly believed Objective The prospect i ve , bidirectional relationship between sleep disturbance and depressed mood was assessed in a school-based sample of adolescents . Method One hundred and thirty-eight Australian adolescents ( mean age time 1 = 15.69 , st and ard deviation = 0.92 ; 64 % male ) completed question naires to assess sleep parameters  and depressed  mood , on two occasions over 1 year . Results Cross-sectional associations were observed between depressed mood and sleep duration , as well as wakefulness in bed . Prospect i ve analyses revealed depressed mood predicted less total sleep time on school nights and a longer latency to sleep onset on weekends 1 year later . There was no prospect i ve support for sleep predicting later depressed mood . Conclusion Contrary to prediction , our results suggest in this case that depressed mood may act as a precursor to poor sleep rather than the converse BACKGROUND Sleep deprivation is common among adolescents and has been associated with adverse behavioral and educational outcomes . However , it is difficult to draw strong causal conclusions because of a dearth of experimental sleep research . In part , this appears related to method ological challenges when working with this population . This study tested the feasibility and behavioral effects of a multi-night , at-home experimental sleep restriction protocol in a sample of adolescents . METHODS Twenty healthy adolescents aged 13.9 - 16.9 years were enrolled in a three-week sleep manipulation protocol using a counterbalanced cross-over experimental design . The protocol included a baseline week , followed in r and om order by a short sleep week ( Monday-Friday nights limited to 6.5 hours time in bed ) and an extended sleep week ( 10 hours lights-out time in bed Monday-Friday nights ) . Sleep was monitored via self-report and objective actigraphy . These were review ed with participants and parents on the Saturdays at the end of each week , when parents and participants also completed behavior rating question naires . RESULTS One participant dropped out of the study , but each of the remaining 19 displayed markedly less sleep in the short sleep condition than the extended sleep condition ( average nightly gap approximately 2.5 hours ) . Data also reflected indirect effects of sleep deprivation that are consistent with an increase in homeostatic sleep drive . Compared to the extended sleep week , parents during the short sleep week reported that the participants displayed significantly greater problems with sleepiness , attention , oppositionality/irritability , behavior regulation , and metacognition . Participant self-report results were similar , though less robust . CONCLUSIONS A multi-night , at-home sleep manipulation protocol for use with adolescents is indeed feasible . This study also provided the first experimental evidence that chronic sleep restriction during adolescence is causally related to a wide range of behavioral deficits AIM Existing literature links poor sleep and anxiety symptoms in adolescents . This pilot study aim ed to develop a practical method through which a program to improve sleep could reach adolescents in need and to examine the feasibility of a mindfulness-based , multi-component group sleep intervention using sleep and anxiety as outcome measures . METHODS Sixty-two grade 9 students ( aged 13 - 15 ) at a girls ' school were screened with the Pittsburgh Sleep Quality Index ( PSQI ) and Spence Children 's Anxiety Scale ( SCAS ) . Ten participants with self-reported poor sleep were enrolled into a six-session program based on Bootzin & Stevens , with added stress/anxiety-specific components . Sessions covered key aspects of basic mindfulness concepts and practice , sleep hygiene , sleep scheduling , evening/daytime habits , stimulus control , skills for bedtime worries and healthy attitudes to sleep . Treatment changes were measured by pre-post scores on the PSQI , SCAS and 7-day actigraphy-measured sleep . RESULTS The program demonstrated high acceptability , with a completion rate of 90 % . Based on effect-size analysis , participants showed significant improvement on objective sleep onset latency ( SOL ) , sleep efficiency and total sleep time ; actigraphy data also showed significantly earlier bedtime , rise time and smaller day-to-day bedtime variation . Post-intervention global PSQI scores were significantly lower than that of pre-intervention , with significant improvement in subjective SOL , sleep quality and sleep-related daytime dysfunction . There were small improvements on some subscales of the SCAS , but change on its total score was minimal . CONCLUSIONS A mindfulness-based , multi-component , in-school group sleep intervention following brief screening is feasible , and has the potential to improve sleep . Its impact on anxiety needs further investigation OBJECTIVE Sleep problems are common and persistent during adolescence and can have negative effects on adolescents ' mood . To date , studies that investigate the effects of sleep extension on adolescents ' sleep and depressive symptoms are still lacking . This study aims to investigate the effects of gradual sleep extension combined with sleep hygiene advice in adolescents with chronic sleep reduction on objective ly measured sleep , self-reported sleep problems and depressive symptoms . METHODS Fifty-five adolescents with chronic sleep reduction ( mean age : 15.44 years ; 85.5 % females ) were included in the study . Participants were r and omly assigned to either a sleep extension group ( gradual sleep extension by advancing bedtimes in the evening and receiving sleep hygiene advice ) or to a control group ( no instruction ) .  Sleep was measured with actigraphy during three weeks , the first week was the baseline week , and the last two weeks were the experimental weeks during which sleep was extended . Other outcome variables were self-reported sleep problems ( daytime sleepiness , symptoms of insomnia and circadian rhythm sleep disorder ) and depressive symptoms , which were assessed before and after the experimental manipulation . RESULTS During the third week of the experiment , adolescents in the sleep extension group had earlier bedtimes , earlier sleep onsets , spent more time in bed and slept longer than adolescents in the control group . Their chronic sleep reduction , insomnia symptoms and depressive symptoms diminished significantly . In addition , there was a trend of improved circadian rhythm sleep disorder symptoms and sleep quality . CONCLUSION Gradual sleep extension combined with sleep hygiene advice seems to have beneficial effects on sleep , self-reported sleep problems and depressive symptoms of adolescents with chronic sleep reduction . Although we can not distinguish between the effects of sleep extension and sleep hygiene advice , the results suggest that advancing bedtimes can extend sleep and improve depressive symptoms Sleep loss is associated with affective disturbances and disorders ; however , there is limited underst and ing of specific mechanisms underlying these links , especially in adolescence . The current study tested the effects of sleep restriction versus idealized sleep on  adolescents  ' emotional experience , reactivity and regulation ( specifically cognitive re appraisal ) . Following 1 week of sleep monitoring , healthy adolescents ( n = 42 ; ages 13 - 17 years ) were r and omized to 1 night of sleep restriction ( 4 h ) or idealized sleep ( 9.5 h ) . The following day , adolescents provided self-reports of affect and anxiety and completed a laboratory-based task to assess : ( 1 ) emotional reactivity in response to positive , negative , and neutral images from the International Affective Picture System ( IAPS ) ; and ( 2 ) ability to use cognitive re appraisal to decrease negative emotional responses . Large effects were observed for the adverse impact of sleep restriction on positive affect and anxiety as well as a medium-sized effect for negative affect , compared to the idealized sleep condition . Subjective 
    Output:
    
Pooled results indicated that less sleep was associated with a 55 % increase in the likelihood of mood deficits .
Positive mood showed the largest relationship with sleep duration , followed by anger , depression , negative affect and anxiety .
Effect sizes also varied according to study design , how sleep was operationalised , and geographical region , but not according to the inclusion of covariates .
Sleep duration has a significant negative impact on a range of mood states in healthy adolescents .
These effects were witnessed across all geographical regions , highlighting that sleep is a universal and modifiable risk factor for preventing mood deficits in this at-risk population