A recently published study about the relationship between sleep time and depression in teens (http://behavioralhealthcentral.com/index.php/20100111172002/Special-Features/teens-who-dont-get-enough-sleep-risk-depression-and-suicide.html) has many people confused.  It was a co-relational study and thus does not confirm causality.  So it is not possible to conclude that going to bed late causes depression in adolescents.  On the other hand, the study does bring the spotlight back on the well known scientifically but less well appreciated complex relationship between sleep and depression in teens.

We have known for a long time that sleep is disturbed in teen depression.  We have also known for a long time that the usual sleep architecture (that is how the different stages of sleep happen during the night) is disturbed in teen depression.  We also know that some teens who get depressed show subtle changes in their sleep architecture before they get depressed. Many years ago my research team reported those findings and we also showed that there were abnormalities in hormone secretion at night in depressed teens. And, we know that forced waking early in the morning may improve symptoms in depression.  So there is clearly something happening in how the brain controls mood and how it controls sleep.

But, it is simplistic and wrong to assume that setting late bedtimes for teen’s causes depression.  This is not the case and it would be foolish to try to tell parents and teens that going to sleep before midnight is protective against depression.  However, there is much for us to learn about sleep and depression in teenagers.  And there is a growing interest amongst researchers in this area.  So stay tuned!

–Stan

So what is this with sleep anyway?

Given what we know at this time, sleep is necessary for brain growth and development.  It is also fundamentally necessary for academic success.  For example, when we sleep, we learn.  Important memories from the previous days are consolidated and the capacity to learn for the next day is refreshed.  And, during the teen years, with the accelerated brain growth and re-organization that occurs during those years – youth actually need more sleep than when they were children.

During the teenage years the child pattern of getting up early and going to bed early shifts to going to bed later and getting up later.  And at the same time, the brain’s need for total sleep time increases – as much as an hour or more per night.  When accentuated by the digital and light enhanced evening environment, staying up later and later becomes the norm for many teens.  And, because the school day usually starts fairly early, students (as the research has shown us) are frequently sleep deprived, sleepy and not at their optimal learning capacity – especially in the first hour or two of classes.  This pattern leads to not enough sleep during the week and this leads to sleep debt – time that needs to be repaid – you guessed it – on the weekend!  This results in a pattern of about 2 hours difference between usual sleep/wake patterns between school days and weekend days for many teenagers.  This is equivalent to a jet lag of 2 hours.  And that happens mostly every week!

One obvious solution to this problem is starting the school day later for high school students.  Indeed, some studies have reported that this results in improved academic performance and one study in Kentucky also found fewer automobile accidents during the later school start trial.  However, this accomodation to the changing teen brain has not proved to be popular with education officials and across most of Canada and the USA, schools still start early and teenagers still come to class tired and not ready to learn.  And guess what?  In many places, exams (including those that take an enormous amount of concentration – such as mathematics) are frequently scheduled for early in the morning! 

So what can be done about this?  Well, changing the school day is not likely to happen, but that would be a really good idea.  Just think, setting up a school protocol to meet the needs of the students – what a novel idea!  For the individual student, trying to get to sleep a little earlier (even one hour earlier) would pay big dividends.  And if that is just as hard as changing the school start time – at least get a good nights sleep before your exam.  Staying up all night and cramming is not helpful.  Getting your beauty rest is.  Isn’t science grand?  Did your grandmother tell you this at some time?

Good piece today in on BBC about how sleep and teens:

Teenage pupils should be given an extra two hours in bed to boost their learning abilities, a Tyneside head teacher has urged.

Dr Paul Kelley, of Monkseaton High School in North Tyneside, said continuous early starts created “teenage zombies” in the classroom.

He said research showed allowing teenagers to begin lessons at 11am had a “profound impact” on learning.

Dr Kelley has already pioneered shorter lessons at the school.

Research suggests teenagers’ brains are wired differently to those of adults and work two hours behind adult time, he said.

Memory tests performed on Monkseaton pupils by neuroscientist Russell Foster, chair of circadian neuroscience at Brasenose College, Oxford, showed the students’ brains worked better in the afternoon.

This suggested young people’s body clocks may shift as they begin their teens - meaning teenagers got up later not because they were lazy, but because they were biologically programmed to do so.

Dr Kelley said depriving teenagers of sleep could have an impact on their mental and physical health as well as their education.

He said evidence had shown rousing teenagers from their beds early resulted in abrupt mood swings, increased irritability, depression, weight gain and reduced immunity to disease.

Read the rest of the article here.

Also see:

Why Teens Need Their Sleep

Holidays for teens usually mean one thing … lots and lots of SLEEP!! But why the heck are teens so tired all the time?

One of the most significant changes linked to brain development that occurs during the teenage years, is related to sleep pattern alterations. Sleep patterns change during adolescence because the brain’s circadian system (biological clock) changes.

This change occurs as a result of a complex dynamic interaction between genetically determined brain development and the impact of the environment on that development. During the teen years the usual childhood pattern of get up early and go to bed early (the so called “lark” pattern) changes to a go to bed late and get up late (the so called “owl”) pattern. This natural change in circadian rhythm is accentuated by the teenager’s environment. Teens are often awash in bright lights late at night, electronic and social stimulation that keep them active into the wee hours, and weekend gatherings that push well into early morning. These factors all converge to set a new go-to-sleep-late and wake-up-late cycle.

Because teenagers stay up much later than younger children do, yet are still forced to wake up early on school days, their total sleep time is shorter (sometimes much shorter) on school days than on weekends, and this disrupts the rhythm of sleep. Teens need about 9 to 9 ½ hours of sleep every night, more than pre-teens need. But because they don’t get anywhere near this amount during the week, many teenagers try to catch up on lost sleep by sleeping in on weekends, which typically annoys their parents. It is important to remember that teenagers do not sleep late on weekends because they are lazy or antisocial, but because they are sleep deprived. They have created a huge sleep debt during the week and are paying it off on the weekend.

During the week many teens are actually sleep deprived. But what does that mean? Sleep deprivation in adolescents can negatively affect the control of behavior, emotion and attention, and is a significant impediment to learning, attainment of social competence and quality of life. Not getting enough sleep can also affect a teenager’s performance in school and other activities that require concentration and focus. Because school schedules are not based on the sleep/wake patterns of teenagers, many students in early morning classes report being less alert, more weary, and having to expend greater effort to pay attention. Reaction times and performance of adolescents are much better in the afternoon than in the morning. With all this sleep deprivation no wonder teens are late for class, sleepy at school, reluctant to be involved in extracurricular activities and cranky. And no wonder many parents find their teenagers to be a royal pain in the mornings!

Decreasing the amount of stimulating activities late at night (TV, phone, internet) is one way to recover lost sleep hours. Unfortunately, many of the social developments that might help correct the problem of adolescent sleep deprivation involve big social policy changes. These include restructuring school curriculums and policy, such as starting school later and ending school later (some school districts have tried this), and creating a broader awareness of the sleep deprivation problem among parents, teachers and physicians.

~ Dr. Stan Kutcher