For the study, the team interviewed nearly 11,000 girls, who are 14-year-old.
"We were quite surprised when we saw the figures and we saw those raw percentages: the fact that the magnitude of association was so much larger for girls than for boys", Kelly said. And where else are they likely to be bombarded with images of unattainable physiques than social media?
The University College London team quizzed 11,000 14-year-olds on their social media exposure and emotions over a fortnight. "All of those four things - the sleep, the cyberharassment, the body image or happiness with appearance, and the self-esteem - they are all linked with the risk of having depression".
For example, while 7.5 per cent of 14-year-old girls and 4.3 per cent of 14-year-old boys have been the victim of online harassment, 35.6 per cent of girls who are depressed have experienced that - double the 17.4 per cent of boys who have done so. Symptoms of depression were measured using the Moods and Feelings Questionnaire. Results revealed that adolescents spending three to five hours of social media per day had a 26 percent increase in depression scores in girls and a 21 percent rise in depression scores in boys.
Chennai: Long-term use of social media is associated with depressive symptoms, says a recent study by Lancet.
In the Philippines, academic and support groups launched in 2017 a study into the "new face of depression on social media", particularly online bashing, as a factor in the rising number of Filipinos suffering from depression and contemplating suicide. Anxiety and poor sleep are both linked to depression. These asked about their social media use and assessed their mental health.
The researchers said the underlying processes of this phenomenon are not well understood.
"Inevitably there is the chicken and egg question, as to whether more dissatisfied children, who to begin with are less pleased with their body shape and have fewer friends then spend more time on social media".
Among teens, "if their sleep is disturbed, and that's because they're using social media a lot, could you cut back on their social media and improve their sleep?"
"Girls, it seems, are struggling with these aspects of their lives more than boys, in some cases considerably so", said Yvonne Kelly, from University College London, who led the team behind the findings.
He added that he often points his patients' families to the American Academy of Pediatrics for tips on how to establish healthy social media habits in the home.
The extent to which social media has embedded itself into the daily lives of people can not be understated.