We know for already a long time that sleep is important for learning. We also know for quite a while that adolescents start staying up late and don’t seem to feel they are tired (though they actually are). Combine this and you can guess the results of this new Swedish study. It shows that adolescents who suffer from sleep disturbance or habitual short sleep duration are less likely to succeed academically compared to those who enjoy a good night’s sleep (do note: correlation!). In a new study involving more than 20,000 adolescents aged between 12 and 19, researchers demonstrated that reports of sleep disturbance and habitual short sleep duration (less than 7 hours per day) increased the risk of failure in school.

The study was led by researcher Christian Benedict and doctoral student Olga Titova at the Department of Neuroscience. The results confirms that sleep may play an important role for adolescents’ performance at school.

The researchers also found that around 30 percent of the adolescents reported regular sleep problems. “Similar observations have been made in other adolescent cohorts, indicating that sleep problems among adolescents have reached an epidemic level in our modern societies”, says Christian Benedict (source). Gender also seems to impact the association strength between sleep quality and academic failure, with greater negative effect on girls (from the paper):

“…girls who reported sleep disturbances had a greater relative risk to fail one or more subjects during the school year than boys with self-reported sleep disturbances. One explanation for the observed gender difference in our study could be that skills that are relevant to perform well at school – e.g. consolidation of facts and events and gain of insight – are more affected by sleep disturbances in girls compared to boys. Another explanation could be that boys, compared to girls – are less complaining about sleep disturbances because of their social roles, which may have weaken the observed association in boys.

Abstract of the research:

Objective
To examine associations of self-reported sleep disturbance and short sleep duration with the risk for academic failure.

Methods
A cohort of ~40.000 adolescents (age range: 12-19 years) who were attending high school grades seven, nine, and secondary year of upper school in the Swedish Uppsala County were invited to participate in the Swedish Life and Health Young Survey (conducted between 2005 and 2011). In addition to the question how many subjects they failed during the school year (outcome variable), subsamples of adolescents also answered questions related to subjective sleep disturbance (n=20.026) and habitual sleep duration (n=4.736) (exposure variables). Binary logistic regression analysis was utilized to explore if self-reported sleep disturbances and habitual short sleep duration (defined as less than 7-8 hours sleep per night) increase the relative risk to fail subjects during the school year (controlled for possible confounders, e.g. body-mass-index).

Results
Adolescents with self-reported sleep disturbances had an increased risk for academic failure (i.e., they failed at least one subject during the school year; OR: Boys, 1.68; Girls, 2.05, both P<0.001), compared to adolescents without self-reported sleep disturbances. In addition, adolescents who reported short sleep duration on both working and weekend days were more likely to fail at least one subject at school than those who slept at least 7-8 h per night (OR: Boys, 4.1; Girls, 5.0, both P<0.001).

Conclusion
Our findings indicate that reports of sleep disturbance and short sleep duration are linked to academic failure in adolescents. Importantly, based on our data, causality cannot be established.