Korean high school students sleep a mere five hours and 27 minutes on average per day, over an hour less than in 2009 and way below the recommended period.
The National Youth Policy Institute conducted a survey of 9,521 students of all grades last year and found that the average night's sleep was a paltry seven hours and six minutes.
Elementary schoolkids got a tolerable eight hours and 19 minutes, but already in middle school this was reduced to seven hours and 12 minutes. More than half the youngsters or 52.8 percent complained of a lack of sleep.
The most common reasons among all children were watching TV and listening to music with 56.2 percent, and online chat and texting with 53.2 percent.
But among high-schoolers a majority of 52.6 percent blamed late-night study. A whopping 61.1 percent elementary schoolkids were kept awake by doing their homework, while middle-schooler settled for entertainment of TV soaps, movies and music with 67.6 percent.
Meanwhile, four out of 10 youngsters surveyed said they think of suicide occasionally or frequently, with 36.9 percent in middle school and 37.3 percent in high school. The figures have risen slightly since a similar survey in 2011, suggesting that pressures are getting worse.
Those most likely to contemplate suicide were generally poorer, performed worse in school, or lived in larger cities.
Bad grades were the main reason for suicidal thoughts with 40.4 percent. Family discord came second with 27.6 percent, and conflicts with peers third with 9.6 percent. The proportion of students who considered suicide because of family discord more than doubled compared to 2009.
Lee Chang-ho of the institute said, "Increasing use of smartphones seems to be relevant to reduced hours of sleep as the survey reveals that many children text, listen to music or play games on their phones."