Excessive screen time disrupts teen sleep, especially girls

By Stephen Beech

Excessive screen time has a negative impact on teenagers' sleep - and on adolescent girls in particular, warns new research.

Spending too long staring at mobile phones or laptop computers can cause sleep disruption and even trigger depression among teenage girls, say scientists.

Swedish researchers found that excessive screen time among adolescents negatively impacts multiple aspects of sleep, which in turn increases the risk of depressive symptoms — particularly for girls.

The Swedish Public Health Agency recently published recommendations that adolescents use no more than two to three hours of daily leisure screen time, partly to promote better sleep.

Previous studies have suggested associations between screen time, sleep disruptions, and depression among teenagers.

However, the research team said that sleep problems and depression often coincide, and the direction of the associations has been unclear.

For the new study, published in the journal PLOS Global Public Health, the research team tracked 4,810 Swedish students aged 12 to 16.

The team collected data on sleep quality and quantity, depressive symptoms, and screen usage three times over the course of a year.

The findings showed that increased screen time led to deteriorated sleep within three months, impacting both the duration and quality of sleep.

Screen time was also found to postpone sleep times towards later hours – disrupting multiple aspects of the human sleep-wake cycle at once.

The researchers said that, among boys, screen time had a "direct" adverse effect on depression after 12 months, while among girls the depressive effect was mediated through sleep disturbances.

They said sleep could explain around half - 38% to 57% - of the association between screen time and depression in girls.

Boys who spent more time on screens also experienced sleep disruptions, according to the findings, but these were not strongly associated to later depression.

Study author Sebastian Hökby of the Karolinska Institute in Sweden, said: “We found that adolescents who reported longer screen times also developed poorer sleep habits over time.

"In turn, this led to increased depression levels, especially among girls.”

He added: “Our results do suggest that less screen time seems healthier, in line with previous World Health Organisation statements.

"If screen times were somehow reduced, for example through public health policies, our results imply that the high burden of depressive states among young Swedish women, and maybe young men, would likely decrease.”