Adolescent brains develop differently depending on whether they are night owls or early birds : ScienceAlert

It’s 11 p.m. weeknight and your teenager still has the bedroom light on. You want them to get enough sleep for school the next day, but it’s a struggle.

Our new research shows what happens to the brains and behavior of young teenagers years after they have become ‘night owls’.

We found that this change in sleep pattern increased the risk of behavioral problems and delayed brain development in later adolescence.

But it’s not all bad news for night owls.

Sleeping habits change

People’s sleep patterns change during adolescence. Teens can stay up longer, sleep later, and have a lie-in the next day.

Many teenagers also shift from being morning larks to owls. They feel more productive and alert later in the evening, prefer to sleep later and wake up later the next day.

This shift to “evening” can conflict with teens’ school and work. Chronic sleep deprivation due to these mismatched sleep schedules may explain why adolescent night owls are at greater risk for emotional and behavioral problems than morning risers.

Emerging research also shows that morning larks and owls have different brain structures. This includes differences in both gray and white matter, which have been linked to differences in memory, emotional well-being, attention and empathy.

Despite these links, it is not clear how this relationship might arise. Does being an owl increase your risk for later emotional and behavioral problems? Or do emotional and behavioral problems lead to more night owls?

In our study, we tried to answer these questions by following the teenagers for many years.

What have we done

We asked more than 200 teens and their parents to fill out a series of questionnaires about teens’ sleep preferences and emotional and behavioral well-being. Participants repeated these questionnaires several times over the next seven years.

The teenagers also had two brain scans, several years apart, to examine their brain development. We focused on mapping changes in the structure of white matter – the brain’s connective tissue that allows our brains to process information and function efficiently.

Previous research has shown that the structure of the white matter of morning larks and night larks differs. However, our study is the first to examine how changes in sleep preferences may affect how white matter grows over time.

Here’s what we found

Adolescents who turned to night owls in early adolescence (around age 12-13) were more likely to have behavioral problems several years later. This included greater aggression, rule breaking and anti-social behaviour.

But they were not at increased risk of emotional problems, such as anxiety or low mood.

Importantly, this relationship did not appear in the reverse direction. In other words, we found that earlier emotional and behavioral problems did not influence whether an adolescent became more of a morning person or a night owl in late adolescence.

Our research also showed that teens who transitioned to being night owls had a different rate of brain development than teens who remained morning-makers.

We found that the owls’ white matter did not increase to the same extent as the adolescent morning larks.

We know that white matter development is important in the adolescent years to support cognitive, emotional and behavioral development.

What are the consequences;

These findings build on previous research showing differences in brain structure between morning larks and night owls. It also builds on previous research that suggests these changes may occur in the teenage years.

Importantly, we show that being an owl increases the risk of having behavioral problems and delayed brain development in later adolescence, and not the other way around.

These findings highlight the importance of focusing on adolescent sleep-wake patterns early in adolescence to support their later emotional and behavioral health. We know that adequate sleep is extremely important for both mental and brain health.

Here’s some good news

It’s not all bad news for night owls. As our research shows, the preferences of the morning lark and the night owl are not fixed. Research shows that we can modify our sleep preferences and habits.

For example, exposure to light (even artificial light) changes our circadian rhythms, which can affect our sleep preferences. Thus, minimizing late-night exposure to bright lights and screens may be a way to modify our preferences and guide us to sleep.

Exposure to light first thing in the morning can also help shift our internal clocks to a more morning-oriented rhythm. You could encourage your teenager to have breakfast outside or go to a balcony or garden before going to school or work.The conversation

Rebecca Cooper, PhD candidate in neuropsychiatry, University of Melbourne. Maria Di Biase, Senior Research Fellow, Psychiatry, The University of Melbourne, and Vanessa Cropley, Senior Research Fellow, The University of Melbourne

This article is republished from The Conversation under a Creative Commons license. Read the original article.

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