Teens who use their cellphones after "lights out" may be at increased risk for mental health problems, as well as lost sleep, a new study from Japan suggests.
In the study, teens who frequently used their cellphones after going to bed were more likely to have poor mental health and suicidal thoughts, and to have harmed themselves, compared with those who did not use their phones at that time of night.
The link held true even after the researchers took into account other factors known to affect mental health, such as alcohol and drug use.
Researchers caution that the study only found an association, and they cannot say that nighttime cellphone use causes mental health problems or reduced sleep. It could be that teens who use phones after bedtime are a specific group, one already prone to mental health troubles.
Researchers at the University of Tokyo investigated close to 18,000 adolescents in in junior high and high school in Japan. Participants answered questions designed to assess symptoms of anxiety and depression, and the occurrence of suicidal thoughts and self-harm.
Lauren Hale, an associate professor of preventive medicine at Stony Brook University in New York, said the findings were not surprising, given what we know about the link between shortened sleep time and poor mental health.
The professor said she is in favor of taking cellphones out of bedrooms. However, further studies will need to be conducted to see if prohibiting late-night cellphone use improves teens' mental health, she said.
The study is published in the October issue of the Journal of Pediatric Psychology.
Source: My Health News Daily