Sleepy, tired teenagers are more likely to commit violent crimes as adults, a new study has found. The study shows that daytime sleepiness may be linked to offences up to 14 years later.
Researchers from the University of Pennsylvania in the US tested 101 15-year-old boys from three schools in England. At the start and end of each afternoon lab session participants were asked to rate their degree of sleepiness on a seven point scale, with one being "unusually alert" and seven being "sleepy."
Brain-wave activity and sweat-rate responses to stimuli, indicating the level of attention a person pays to a tone being played over headphones was also measured.
Data about anti-social behaviour was collected, both self-reported from the study participants, as well as from two or three teachers who had worked with each teen for at least four years.
Finally a search was carried out to find the criminal records of the participants, focusing on violent crimes, property offences and those crimes for which participants were convicted.
It was learnt that 17 per cent of participants had committed a crime by that point in adulthood.
"It's the first study to our knowledge to show that daytime sleepiness during teenage years are associated with criminal offending 14 years later," said Adrian Raine, a professor in the University of Pennsylvania.
"Is it the case that low social class and early social adversity results in daytime drowsiness, which results in inattention or brain dysfunction, which results 14 years later in crime? The answer's yes," Raine said.
"Daytime drowsiness is associated with poor attention. Take poor attention as a proxy for poor brain function. If you've got poor brain functioning, you're more likely to be criminal," Raine added.
The researchers stress that drowsiness in and of itself does not always predispose teenager to become anti-social.
Many children with sleep problems do not become lawbreakers. However, the researchers did find that those with sleepiness and a greater frequency of anti-social behaviour during teenage years had higher odds of a life of crime later.
The research was published in the Journal of Child Psychology and Psychiatry.