Sleep from thirteen to eighteen
Your teenager is not lazy. Somewhere in adolescence their body clock moved later, and school still starts before it is ready. Here is what actually changed, what the evidence supports, and what is worth raising with a clinician.
How much sleep teenagers actually need
Teenagers aged 13 to 18 need 8 to 10 hours in 24. Most do not get it, and that gap is the single largest sleep problem in this age group.
Aged 13 to 18
Across 24 hours. American Academy of Sleep Medicine consensus statement, endorsed by the American Academy of Pediatrics (Journal of Clinical Sleep Medicine, 2016).
Fall short
23.2 percent of US high school students got enough sleep in 2023, down from 32 percent in 2013 (Centers for Disease Control and Prevention, Youth Risk Behavior Survey trends report, 2025).
Probably generous
These figures come from teenagers estimating their own sleep. When sleep is measured rather than reported, the totals are usually lower, not higher.
The body clock really does move
This is the part most worth understanding, because it changes what you ask of your teenager and what you stop arguing about.
Two things shift during adolescence, and they push in the same direction. The first is timing. Melatonin, the hormone that marks the start of the body's biological night, starts being released about an hour later across adolescence, measured directly in the same young people followed over years (PLoS One, 2014). The second is pressure. The drive to sleep builds up more slowly as teenagers mature. In a carefully controlled laboratory study, the build-up took around 9 hours in early puberty and around 15 hours by full maturity (Sleep, 2005). That study was small, so hold the exact numbers lightly, but the direction is consistent.
Put those together and a teenager at 10pm is in a genuinely different state from a nine year old at 10pm. Not defiant. Not yet sleepy.
One popular explanation is wrong and worth dropping. Teenagers do not have a longer internal clock than adults. Measured directly, the free running clock ran at 24.19 hours in adolescents and 24.22 hours in adults, with no meaningful difference (Journal of Sleep Research, 2018). The delay comes from when the clock is set and how slowly sleep pressure builds, not from the length of the day it keeps.
When late nights become a disorder
There is a point where a late body clock stops being a phase and becomes a diagnosable problem, called delayed sleep-wake phase disorder.
In a study of 9,338 Norwegian adolescents aged 16 to 19, 3.3 percent met the criteria (BMC Public Health, 2013). Estimates elsewhere range from about 1 percent to over 8 percent, which tells you how much the definition used affects the answer.
The most useful way to tell it apart at home is what happens in the holidays. A teenager with a delayed clock, left to their own schedule, sleeps well and sleeps enough. They just do it late. A teenager who sleeps badly whatever the schedule has something else going on, and insomnia is the more likely explanation. The formal criteria also require the pattern to have lasted at least three months and to be causing real difficulty.
Treatment guidance exists, and every recommendation in it is rated weak. Timed melatonin at about 0.15 mg per kg, given 1.5 to 2 hours before their usual bedtime, and morning light after waking, combined with a gradually shifting schedule (American Academy of Sleep Medicine clinical practice guideline, Journal of Clinical Sleep Medicine, 2015). Note how different that is from the usual approach at home. It is a small dose, given in the early evening, where the timing is doing the work rather than the amount.
School start times
The American Academy of Pediatrics recommends that middle and high schools start no earlier than 8:30am (policy statement, Pediatrics, 2014). The American Academy of Sleep Medicine takes the same position (2017).
When Seattle moved high school start times from 7:50am to 8:45am, researchers measured students' sleep with wrist monitors before and after in the same schools. Sleep went up by a median of 34 minutes (Science Advances, 2018). That is the clearest finding in this area, and the mechanism is not mysterious.
Beyond sleep duration, the picture is less settled than campaigning tends to suggest. A systematic review covering 297,994 students rated the overall certainty of the evidence as very low, with mixed results on academic outcomes (Cochrane Database of Systematic Reviews, 2017).
One widely repeated claim deserves correcting. A 2008 study reported a 16.5 percent drop in teen car crashes after a district moved its start time later. When federal researchers re-analysed the same data with a more rigorous method, that reduction did not hold up, and a second district showed roughly a 14 percent reduction that reached significance only on a one-sided test (National Highway Traffic Safety Administration, 2015). Later start times are worth arguing for on sleep alone. The crash argument is weaker than it is usually presented.
Catching up at the weekend does not work
The Saturday lie-in feels like repayment. Measured properly, it does not settle the debt.
Fifty-seven healthy adolescents aged 15 to 19 spent 15 days in a sleep laboratory. Five nights restricted to 5 hours, then two recovery nights of 9 hours, then a second round. Attention got worse across the restricted nights and did not return to baseline after the two recovery nights. It then deteriorated faster during the second restriction (Sleep, 2017). The authors' conclusion was blunt: weekend catch-up, even with naps added, is worse than simply having the chance to sleep 9 hours every night.
There is a second cost. Sleeping in on the weekend shifts the body clock later still, which is part of why Sunday night and Monday morning are so reliably difficult. In adults, a similar pattern of weekday restriction and weekend recovery left insulin sensitivity worse than baseline (Current Biology, 2019). That study was in adults, so read it as a signal rather than as teenage data.
What helps more than a long Saturday is a wake time that does not move by more than about an hour between school days and free days.
The phone overnight
The evidence on screens is strongest for one specific thing, and it is not total hours.
A meta-analysis of 20 studies covering 125,198 young people found that using a device at bedtime roughly doubled the odds of not getting enough sleep, and that simply having a device within reach at bedtime, without using it, was associated with almost as much (JAMA Pediatrics, 2016). Every study in it looked at young people at a single point in time, so it cannot tell us which came first.
In a large study of 10,280 early adolescents, leaving the phone's ringer on overnight, being woken by notifications, and using a device after waking in the night were each associated with more trouble sleeping (Sleep Health, 2023).
Against that, the largest preregistered analysis, covering 50,212 young people, found each hour of screen time associated with around 3 minutes less sleep, under 2 percent of the difference between individuals (Journal of Pediatrics, 2019).
Taken together the practical message is narrow and worth acting on. The phone charging outside the bedroom overnight, and notifications off, is a defensible thing to insist on. Counting hours of screen time is not.
Caffeine and energy drinks
About 73 percent of US children and adolescents consumed caffeine on a given day, with coffee and energy drinks taking a growing share (Pediatrics, 2014).
In 98 adolescents whose sleep was measured with EEG at home over seven consecutive nights, more caffeine meant longer to fall asleep, less total sleep, and lower sleep efficiency. Afternoon and evening caffeine drove the effect. The study also found the loop running both ways: a worse night predicted more caffeine the following afternoon (Journal of Clinical Sleep Medicine, 2022).
Energy drinks specifically stand out. Among 1,353 Norwegian adolescents aged 15 to 16, those drinking them four or more times a week slept about 57 minutes less than non-consumers and took over 25 minutes longer to fall asleep (BMC Public Health, 2022). That study compared groups at one point in time, so some of that gap will reflect other differences between those teenagers. The American Academy of Pediatrics position is that caffeinated energy drinks have no place in the diet of children and adolescents (2011).
The most useful rule is about timing rather than a total. Caffeine after early afternoon is the part that shows up in measured sleep.
Sleep and mood
Sleep and mental health travel together in adolescence. The direction of the arrow is less settled than most coverage implies, and that matters for what you do about it.
Pooling 22 prospective studies, disturbed sleep predicted later depression in children and young people, but the authors described the effect as small, found substantial publication bias, and did not claim that sleep loss causes depression (JAMA Network Open, 2021). A separate review of 74 studies covering 361,505 adolescents found the strongest signal was not depression but the loss of positive mood, meaning less enthusiasm and less enjoyment (Sleep Medicine Reviews, 2020).
The relationship runs in both directions. Anxiety and low mood disturb sleep, and disturbed sleep worsens mood (Sleep, 2013). Treating one as the cause of the other will sometimes mean missing something that needs its own attention.
The strongest evidence points somewhere more useful. In a randomised trial of 708 young people aged 15 to 25 with insomnia and early signs of low mood, six weeks of app-based treatment for the insomnia reduced new episodes of major depression over the following year from 18 percent to 10 percent (PLOS Medicine, 2025). The average participant was 22, so this is young adult data as much as teenage data. It supports treating sleep as worth addressing in its own right.
If you are worried about your teenager's mood, please raise it with your own clinician rather than waiting to see whether better sleep fixes it.
Melatonin for teenagers
Melatonin is easy to buy and widely used, which makes it easy to assume it is well understood. It is not.
When researchers tested 25 melatonin gummies, 22 were inaccurately labelled, with actual content ranging from 74 to 347 percent of the label, and one containing no melatonin at all (JAMA, 2023). An earlier analysis of 31 supplements found unlabelled serotonin in around a quarter of them (Journal of Clinical Sleep Medicine, 2017).
On how well it works, pooled evidence from eight randomised trials in young people with long standing insomnia found sleep came about 18 minutes sooner and total sleep rose by about 30 minutes, with certainty rated low to very low. The authors stated plainly that it should never be the first choice in this age group (EClinicalMedicine, 2023).
The American Academy of Sleep Medicine advises treating melatonin like any other medicine, keeping it out of reach of younger children, speaking to a pediatric health professional first, and choosing a product with the USP Verified Mark (health advisory, 2022). If your teenager has a delayed body clock, the timing described earlier matters more than the dose.
Worth mentioning at your next visit
Teenage sleep problems are easy to write off as normal teenage behaviour. These are the ones worth saying out loud.
- Cannot fall asleep before the early hours, even when tired and trying
- Sleeps well and long on holidays, but only if allowed to start late
- Falls asleep in class, or while sitting still during the day
- Snoring most nights, or pauses in breathing
- Legs that ache or feel restless at bedtime
- Low mood, anxiety, or a change in how they are coping
- Energy drinks, or caffeine after the early afternoon
- Melatonin taken for more than a few weeks
- Missing school in the mornings
Have another child at a different age?
What is normal at six months is not normal at sixteen years. Each age has its own page.
Where this comes from
- Paruthi S, et al. Recommended amount of sleep for pediatric populations: a consensus statement of the American Academy of Sleep Medicine. Journal of Clinical Sleep Medicine, 2016;12(6):785 to 786. Source of the 8 to 10 hour range.
- Centers for Disease Control and Prevention. Youth Risk Behavior Survey data summary and trends report: dietary, physical activity and sleep behaviors, 2013 to 2023. Published 2025. Source of the 23.2 percent and 32 percent figures.
- Crowley SJ, et al. A longitudinal assessment of sleep timing, circadian phase, and phase angle of entrainment across human adolescence. PLoS One, 2014;9(11):e112199.
- Jenni OG, Achermann P, Carskadon MA. Homeostatic sleep regulation in adolescents. Sleep, 2005;28(11):1446 to 1454. Source of the 9 hour and 15 hour build-up figures.
- Crowley SJ, Eastman CI. Free-running circadian period in adolescents and adults. Journal of Sleep Research, 2018;27(5):e12678. Source of the 24.19 and 24.22 hour figures.
- Sivertsen B, et al. Delayed sleep phase syndrome in adolescents: prevalence and correlates in a large population based study. BMC Public Health, 2013;13:1163.
- Auger RR, et al. Clinical practice guideline for the treatment of intrinsic circadian rhythm sleep-wake disorders. Journal of Clinical Sleep Medicine, 2015;11(10):1199 to 1236. Source of the melatonin timing and dose.
- Adolescent Sleep Working Group, American Academy of Pediatrics. School start times for adolescents. Pediatrics, 2014;134(3):642 to 649.
- Watson NF, et al. Delaying middle school and high school start times promotes student health and performance: an American Academy of Sleep Medicine position statement. Journal of Clinical Sleep Medicine, 2017;13(4):623 to 625.
- Dunster GP, et al. Sleepmore in Seattle: later school start times are associated with more sleep and better performance in high school students. Science Advances, 2018;4(12):eaau6200. Source of the 34 minute figure.
- Marx R, et al. Later school start times for supporting the education, health and well-being of high school students. Cochrane Database of Systematic Reviews, 2017;7:CD009467.
- Foss RD, et al. High school start times and teen driver crashes. National Highway Traffic Safety Administration, 2015. Report DOT HS 812 221.
- Lo JC, et al. Neurobehavioral impact of successive cycles of sleep restriction with and without naps in adolescents. Sleep, 2017;40(2):zsw042.
- Depner CM, et al. Ad libitum weekend recovery sleep fails to prevent metabolic dysregulation during a repeating pattern of insufficient sleep and weekend recovery sleep. Current Biology, 2019;29(6):957 to 967. Conducted in adults.
- Carter B, et al. Association between portable screen-based media device access or use and sleep outcomes: a systematic review and meta-analysis. JAMA Pediatrics, 2016;170(12):1202 to 1208.
- Nagata JM, et al. Bedtime screen use behaviors and sleep outcomes: findings from the Adolescent Brain Cognitive Development study. Sleep Health, 2023;9(4):497 to 502.
- Przybylski AK. Digital screen time and pediatric sleep: evidence from a preregistered cohort study. Journal of Pediatrics, 2019;205:218 to 223.
- Branum AM, Rossen LM, Schoendorf KC. Trends in caffeine intake among US children and adolescents. Pediatrics, 2014;133(3):386 to 393.
- Lunsford-Avery JR, et al. Impact of daily caffeine intake and timing on electroencephalogram-measured sleep in adolescents. Journal of Clinical Sleep Medicine, 2022;18(3):877 to 884.
- Kaldenbach S, et al. Sleep and energy drink consumption among Norwegian adolescents. BMC Public Health, 2022;22:534. Source of the 57 minute figure.
- Marino C, et al. Association between disturbed sleep and depression in children and youths: a systematic review and meta-analysis of cohort studies. JAMA Network Open, 2021;4(3):e212373.
- Short MA, et al. The relationship between sleep duration and mood in adolescents: a systematic review and meta-analysis. Sleep Medicine Reviews, 2020;52:101311.
- Alvaro PK, Roberts RM, Harris JK. A systematic review assessing bidirectionality between sleep disturbances, anxiety, and depression. Sleep, 2013;36(7):1059 to 1068.
- Chen SJ, et al. Effectiveness of app-based cognitive behavioral therapy for insomnia on preventing major depressive disorder in youth with insomnia and subclinical depression: a randomized clinical trial. PLOS Medicine, 2025;22(1):e1004510.
- Cohen PA, et al. Quantity of melatonin and CBD in melatonin gummies sold in the US. JAMA, 2023;329(16):1401 to 1402.
- Erland LAE, Saxena PK. Melatonin natural health products and supplements: presence of serotonin and significant variability of melatonin content. Journal of Clinical Sleep Medicine, 2017;13(2):275 to 281.
- Edemann-Callesen H, et al. Use of melatonin in children and adolescents with idiopathic chronic insomnia: a systematic review, meta-analysis, and clinical recommendation. EClinicalMedicine, 2023;61:102048.
- American Academy of Sleep Medicine. Health advisory: melatonin use in children and adolescents. Adopted 2022, published in Journal of Clinical Sleep Medicine, 2022;18(12):2857 to 2859.
This page provides educational and informational content on pediatric sleep health for general purposes only. Nothing here constitutes medical advice, a clinical diagnosis, or a substitute for professional medical consultation. Parents and caregivers should consult their child's physician before changing care or treatment. In a medical emergency, contact your local emergency services immediately.
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