The study, published in The Lancet Child and Adolescent Health journal, suggests that while frequent use of social media does appear to be linked to poorer mental health, the effects are not direct. Instead, mental health issues among teenagers could be due to cyber bullying and social media use displacing other activities, such as sleep and exercise.

As part of the study, researchers from University College London (UCL) and Imperial College London analysed data from almost 10,000 school children as they progressed from age 13 to 16 during 2013-2015.

They found that 43 per cent of girls and boys used social media more than three times a day in the first year, rising to 69 per cent in the third. Those who check the sites at this frequency – compared to logging in weekly or less – in the first year were 31 per cent more likely to experience psychological distress the following year.

In 2014, 28 per cent of female ‘very frequent’ social media users reported psychological distress on the general health questionnaire, compared with 20 per cent of those using it weekly or less. In boys, it rose from 10 per cent to nearly 15 per cent.

For girls, the harmful effect was driven primarily by online bullying and also preventing them engaging in protective activities such as sleeping well and exercising. The researchers also said they were less sure why boys were affected.

Professor Russell Viner, from the UCL Great Ormond Street institute of child health, has advised parents to keep screens out of their children’s bedrooms to avoid disrupting sleep and encourage their children to get enough exercise and spend time with friends in person.

“Young people’s use of social media and smartphones is an ongoing concern for today’s parents,” he said. “We found no convincing evidence that social media is harmful in and of itself.

“In girls, the harmful impact of social media on mental health and wellbeing was almost entirely accounted for by cyber bullying, inadequate sleep and inadequate physical activity.

“The same picture was partially seen in boys, although more research is needed to explore the gender differences.”

Viner also added: “While we obsess a lot about social media, how much do we obsess about how much our young people sleep? Not very much, but it is a more important factor, actually, in determining their mental health.”

Dr Dasha Nicholls, from Imperial College London, also said that adults should ask children about whether they have been bullied online. She said: “Parents and others need to know what their young people’s social environment is online as much as they do in the real world.”

In England, more than 90 per cent of teenagers use the internet for social networking and the study is the first with enough participants to make it representative of the whole of the country. It is also the first to follow social media use and mental health over time.

In the first year of the study, the researchers asked the participants about their social media habits, finding that the majority used social media frequently, using networks, instant messaging or photo-sharing services three or more times daily.

In the second year of the study, participants were also quizzed about their levels of psychological distress and asked about sleep and exercise habits, as well as if they had been cyber bullied. Furthermore, in the final year, the teenagers were asked about their life satisfaction, happiness and anxiety.

Very frequent social media use across 2013 and 2014 predicted a subsequent lowering of wellbeing in girls, with girls who persistently used social media very frequently reporting lower life satisfaction and happiness and greater anxiety in 2015.

The authors found that almost all of the effect on girls’ wellbeing in 2015 was down to cyber bullying, reduced sleep of less than eight hours a night and reduced physical activity, e.g. exercising less than once a week.

Nicholls said: “The clear sex differences we discovered could simply be attributed to girls accessing social media more frequently than boys, or to the fact that girls had higher levels of anxiety to begin with.

“Cyber bullying may be more prevalent among girls, or it may be more closely associated with stress in girls than in boys.

“However, as other reports have also found clear sex differences, the results of our study make it all the more important to undertake further detailed studies of the mechanisms of social media effects by gender.”

In related news, researchers from the University of East Anglia, the University of Greenwich and Auckland University of Technology sent a small group of people on technology-free travels in a bid to understand their reaction when disconnected from the online world.

During the course of a digital-detox holiday, 24 participants were asked to share their emotion changes when scrapping their digital lifestyles, such as living without the ability to share a photo online or get help with directions from Google Maps.

The study found that most of the participants disconnected from their smartphones for more than 24 hours learned more about sights, places and beaches because they were forced to talk to other travellers, especially locals.

Those who travelled to urban destinations were more likely to experience anxieties and frustrations due to lack of navigation, instant information access and digital word-of-mouth recommendation seeking. On the other hand, people in rural and natural destinations felt withdrawal symptoms related to being unable to report safety or kill time.

“Our participants reported that they not only engaged more with other travellers and locals during their disconnected travels, but that they also spent more time with their travel companions,” said Dr Wenjie Cai, from the University of Greenwich.

“We found that some participants embraced and enjoyed the disconnected experience straightaway or after struggling initially, while for others it took a little bit longer to accept the disconnected experience.

“Many also pointed out that they were much more attentive and focused on their surroundings while disconnected, rather than getting distracted by incoming messages, notifications or alerts from their mobile apps.”

In recent months there have been a series of studies investigating social media use and its links to mental health issues found in young people.

A major study using ‘best practice’ statistical and methodical techniques, which was published in April, raised fresh doubts on the much-discussed theory that time spent staring at screens is directly responsible for poor mental health among young people.

In March, positive lifestyle magazine ‘Shout’, aimed at young girls aged 11-14 years old, conducted a UK-wide poll on the main causes of mental ill-health among teenagers. The survey found that around eight in 10 teenage girls felt under pressure to get likes and followers on social media apps such as Instagram.

MPs in the UK have also voiced their stance on social media platforms, previously saying addiction to social media should be classed as a disease, as they called for tough new regulations to protect children from firms operating in an “online Wild West”.

The study, published in The Lancet Child and Adolescent Health journal, suggests that while frequent use of social media does appear to be linked to poorer mental health, the effects are not direct. Instead, mental health issues among teenagers could be due to cyber bullying and social media use displacing other activities, such as sleep and exercise.

As part of the study, researchers from University College London (UCL) and Imperial College London analysed data from almost 10,000 school children as they progressed from age 13 to 16 during 2013-2015.

They found that 43 per cent of girls and boys used social media more than three times a day in the first year, rising to 69 per cent in the third. Those who check the sites at this frequency – compared to logging in weekly or less – in the first year were 31 per cent more likely to experience psychological distress the following year.

In 2014, 28 per cent of female ‘very frequent’ social media users reported psychological distress on the general health questionnaire, compared with 20 per cent of those using it weekly or less. In boys, it rose from 10 per cent to nearly 15 per cent.

For girls, the harmful effect was driven primarily by online bullying and also preventing them engaging in protective activities such as sleeping well and exercising. The researchers also said they were less sure why boys were affected.

Professor Russell Viner, from the UCL Great Ormond Street institute of child health, has advised parents to keep screens out of their children’s bedrooms to avoid disrupting sleep and encourage their children to get enough exercise and spend time with friends in person.

“Young people’s use of social media and smartphones is an ongoing concern for today’s parents,” he said. “We found no convincing evidence that social media is harmful in and of itself.

“In girls, the harmful impact of social media on mental health and wellbeing was almost entirely accounted for by cyber bullying, inadequate sleep and inadequate physical activity.

“The same picture was partially seen in boys, although more research is needed to explore the gender differences.”

Viner also added: “While we obsess a lot about social media, how much do we obsess about how much our young people sleep? Not very much, but it is a more important factor, actually, in determining their mental health.”

Dr Dasha Nicholls, from Imperial College London, also said that adults should ask children about whether they have been bullied online. She said: “Parents and others need to know what their young people’s social environment is online as much as they do in the real world.”

In England, more than 90 per cent of teenagers use the internet for social networking and the study is the first with enough participants to make it representative of the whole of the country. It is also the first to follow social media use and mental health over time.

In the first year of the study, the researchers asked the participants about their social media habits, finding that the majority used social media frequently, using networks, instant messaging or photo-sharing services three or more times daily.

In the second year of the study, participants were also quizzed about their levels of psychological distress and asked about sleep and exercise habits, as well as if they had been cyber bullied. Furthermore, in the final year, the teenagers were asked about their life satisfaction, happiness and anxiety.

Very frequent social media use across 2013 and 2014 predicted a subsequent lowering of wellbeing in girls, with girls who persistently used social media very frequently reporting lower life satisfaction and happiness and greater anxiety in 2015.

The authors found that almost all of the effect on girls’ wellbeing in 2015 was down to cyber bullying, reduced sleep of less than eight hours a night and reduced physical activity, e.g. exercising less than once a week.

Nicholls said: “The clear sex differences we discovered could simply be attributed to girls accessing social media more frequently than boys, or to the fact that girls had higher levels of anxiety to begin with.

“Cyber bullying may be more prevalent among girls, or it may be more closely associated with stress in girls than in boys.

“However, as other reports have also found clear sex differences, the results of our study make it all the more important to undertake further detailed studies of the mechanisms of social media effects by gender.”

In related news, researchers from the University of East Anglia, the University of Greenwich and Auckland University of Technology sent a small group of people on technology-free travels in a bid to understand their reaction when disconnected from the online world.

During the course of a digital-detox holiday, 24 participants were asked to share their emotion changes when scrapping their digital lifestyles, such as living without the ability to share a photo online or get help with directions from Google Maps.

The study found that most of the participants disconnected from their smartphones for more than 24 hours learned more about sights, places and beaches because they were forced to talk to other travellers, especially locals.

Those who travelled to urban destinations were more likely to experience anxieties and frustrations due to lack of navigation, instant information access and digital word-of-mouth recommendation seeking. On the other hand, people in rural and natural destinations felt withdrawal symptoms related to being unable to report safety or kill time.

“Our participants reported that they not only engaged more with other travellers and locals during their disconnected travels, but that they also spent more time with their travel companions,” said Dr Wenjie Cai, from the University of Greenwich.

“We found that some participants embraced and enjoyed the disconnected experience straightaway or after struggling initially, while for others it took a little bit longer to accept the disconnected experience.

“Many also pointed out that they were much more attentive and focused on their surroundings while disconnected, rather than getting distracted by incoming messages, notifications or alerts from their mobile apps.”

In recent months there have been a series of studies investigating social media use and its links to mental health issues found in young people.

A major study using ‘best practice’ statistical and methodical techniques, which was published in April, raised fresh doubts on the much-discussed theory that time spent staring at screens is directly responsible for poor mental health among young people.

In March, positive lifestyle magazine ‘Shout’, aimed at young girls aged 11-14 years old, conducted a UK-wide poll on the main causes of mental ill-health among teenagers. The survey found that around eight in 10 teenage girls felt under pressure to get likes and followers on social media apps such as Instagram.

MPs in the UK have also voiced their stance on social media platforms, previously saying addiction to social media should be classed as a disease, as they called for tough new regulations to protect children from firms operating in an “online Wild West”.