Concerns about the impact of social media on vulnerable people come amid suicides such as that in 2017 of the 14-year-old schoolgirl, who was found to have viewed harmful content online.
The Royal College of Psychiatrists said a proposed 2 per cent levy on the UK revenues of major tech companies does not go far enough.
Instead, it wants the so-called “turnover tax” to apply to international turnover and for some of the money from it to be used for mental health research.
Molly’s father, Ian Russell, spoke of the urgent need for greater action in an emotional foreword to the report, in which he described the “wrecking ball of suicide“ that “smashed brutally” into his family, blaming “pushy algorithms”.
He said of her social media accounts: “Among the usual schoolfriends, pop groups and celebrities followed by 14-year-olds, we found bleak depressive material, graphic self-harm content and suicide-encouraging memes.
“I have no doubt that social media helped kill my daughter.”
Mr Russell also detailed one of Molly’s final notes which described how she felt “with heart-breaking clarity”.
“I’m the weird sister, quiet daughter, depressed friend, lonely classmate,” she wrote.
“I’m nothing, I’m worthless, I’m numb, I’m lost, I’m weak, I’m gone. I’m sorry. I’ll see you in a little while. I love you all so much. Have a happy life. Stay strong xxx.”
While welcoming the government’s White Paper on online harms, the College’s report calls for an independent regulator with powers to be able to establish a protocol for the sharing of data from social media companies with universities for research, such as behavioural data.
It also points to evidence that increased social media use may result in poorer mental health, particularly in girls.
Dr Bernadka Dubicka, chairwoman of the child and adolescent faculty at the Royal College of Psychiatrists and co-author of the report, said: “As a psychiatrist working on the front line, I am seeing more and more children self-harming and attempting suicide as a result of their social media use and online discussions.
“Their research will help shine a light on how young people are interacting with social media, not just how much time they spend online.
“Self-regulation is not working. It is time for government to step up and take decisive action to hold social media companies to account for escalating harmful content to vulnerable children and young people.”
Claire Murdoch, NHS national director for mental health, said: “If these tech giants really want to be a force for good, put a premium on their users well-being and take their responsibilities seriously then they should do all that they can to help researchers better understand how they operate and the risks posed – until then they cannot confidently say whether the good outweighs the bad.”
The biggest social network, Facebook, said it is “already taking a number of the steps recommended” in the report.
“We remove harmful content from our platforms and provide support for those who search for it,” a spokesman said.
“We are working closely with organisations such as the Samaritans and the Government to develop industry guidelines in this area.”
A Government spokesman said: “We are developing world-leading plans to make the UK a safer place to be online. This includes a duty of care on online companies, overseen by an independent regulator with tough enforcement powers, to hold them to account.
“The regulator will have the power to require transparency reports from companies outlining what they are doing to protect people online. These reports will be published so parents and children can make informed decisions about their internet use.”
For confidential support call Samaritans on 116 123.
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