Depression and self-harm are on the rise among Britain’s teenagers, according to a large-scale study.
Youngsters are also far more likely to suffer poor body image compared with a decade ago, while parents are more likely to say their teenagers have friendship issues and emotional problems.
The study of more than 16,000 14-year-olds was published after the Government vowed to crack down on harmful content on social media sites following the death of 14-year-old Molly Russell, who took her own life in 2017.
Her father has said Instagram helped to kill his daughter after he found she had been viewing graphic images of self-harm on the site.
Instagram has since said it will remove all graphic images of self-harm, with other social media sites taking similar action.
The new study, led by University College London’s Centre for Longitudinal Studies, examined data for two sets of children.
The first set of 5,627 were born in 1991-92, while the second set of 11,318 were born a decade later in 2000-02.
Both groups are being followed long-term as part of major studies and the data was statistically adjusted to ensure the groups could be compared at 14.
Researchers found that 14-year-olds nowadays are far more likely to report feeling depressed – rising more than 50% across the decade, from 9% in 2005 to 14.8% in 2015.
Self-harm has also shown a large increase, from 11.8% of youngsters born in the early 1990s to 14.4% of those born at the turn of the millennium.
While girls from both groups were more likely than boys to be depressed and to self-harm, the rate at which these problems were rising was the same for both genders, researchers said.
Parents were also around twice as likely to report their youngster having emotional difficulties, behavioural problems and issues with peer groups than those whose children were born in the early 1990s.
The research also found that teenagers nowadays are far more likely to skip the recommended eight hours of sleep, with 12% not having eight hours compared with 6% in the other group.
They were also more likely to be obese, while a greater proportion also saw themselves as overweight (up from 27% to 33%).
However, the researchers found that some health behaviours typically associated with poor mental health fell across the decade, with fewer 14-year-olds now trying cigarettes or cannabis, drinking alcohol, getting involved in anti-social behaviour or having sex.
Rates of 14-year-olds punching or kicking someone on purpose have dropped from 40% to 28%, and teenagers committing acts of vandalism have decreased from 6% to 2%.
More than 52% of the those born in the early 1990s had tried alcohol by 14, compared with less than 44% of those born a decade later.
Experts concluded that poor sleep, obesity and poor body image are becoming more common, suggesting the risk factors associated with mental ill-health may be changing.
Dr Suzanne Gage, co-author of the study, said: “It has seemed for a while that mental health difficulties in young people are on the rise, but this study really highlights the scale at which this increase might be occurring.
“It’s not just that we’re getting better at measuring depressive symptoms, as identical questions about depressive symptoms were asked in both cohorts.
“The next step is to understand why these increases are occurring, so young people can be supported better.”
NHS data for England shows there were 3,590 hospital admissions for self-harm among those aged 13 to 17 in 2017-18, up from 1,181 in 2007-08.
Dr Bernadka Dubicka, chairwoman of the child and adolescent faculty at the Royal College of Psychiatrists, said: “This study is a wake-up call to the different pressures today’s teenagers are under and the impact these may have on their mental health.
“We welcome NHS England’s commitment to improving support for children and young people with mental illnesses in the NHS long-term plan, but to meet its aspirations focus is urgently needed on increasing numbers of skilled staff working in this area to ensure demand for services is met.”