A lack of sleep among teenagers who are spending the night hours on social media can cause depression and anxiety, according to a study.
Scientists measured the sleep quality and social media use of 467 teenagers and found that pressure to be available online 24 hours a day and respond to messages impacted on mental health issues.
Analysis showed that overall and night-time specific social media use, along with emotional investment in social media, were related to poorer sleep quality, lower self-esteem as well as higher anxiety and depression levels.
Led by Dr Heather Cleland Woods of the University of Glasgow, the study suggested parents should ensure children "switch off" at night.
The study is being presented at the British Psychological Society conference in Manchester.