Staying Healthy Parents News Now Teens Who Use Mobile Devices After Bedtime at Increased Depression Risk By Holly Lebowitz Rossi Published on October 8, 2012 Share Tweet Pin Email In the study, researchers investigated nearly 18,000 children in junior high and high schools in Japan, with subjects answering questions about their mental health, in addition to sleep and mobile phone habits. The study follows prior research that finds poor sleep is associated with mental problems in teens. For example, a study published last year in the Journal of Psychiatric Research found teens who had difficulty sleeping were at an increased risk for suicidal thoughts. Image: Cell phone, via Shutterstock Was this page helpful? Thanks for your feedback! Tell us why! Other Submit