A DRAMATIC rise in the use of computers and social media is wreaking havoc on the health of young people, according to an international obesity report which found that Scottish teenagers spend more time online or gaming than almost any other European nation.

Social media was blamed for the "continuous steep increase" between 2002 and 2014 in the proportion of children and teenagers using technology for two hours or more each weekday for non-gaming activities.

Experts warned it was driving sedentary behaviour and storing up problems such as diabetes, cardiovascular disease and mental health issues, with the vast majority of young people also failing to take the recommended level of exercise each day.

The World Health Organisation report, which will be presented at a conference in Portugal today, found that 90 per cent of 15-year-old boys and girls in Scotland spend at least two hours every day using devices such as smartphones, laptops, tablets and desktop computers for both gaming and non-gaming activities. Only Sweden and the Netherlands had similarly high levels.

Lead author Dr Jo Inchley, assistant director of the Child and Adolescent Health Research Unit at St Andrews University, said: "We know that a positive impact of social media is social connectedness and the sense of interaction. But we also know there are risks, such as cyber bullying and impact on mental health, as well as things like missing out on sleep.

"Also, there are longer-term impacts on physical health from being sedentary."

She said these risks included cardiovascular disease, obesity and Type 2 diabetes.

She added: "One of the main challenges for us is that this kind of activity (social media and computer use) is so much part of young people's lives these days, how do we manage this and the health risks associated with it?

"It's about reducing time being spent sedentary, and ensuring that children still have opportunity to be active. We really need to start addressing these challenges now."

Tam Fry, chairman of the National Obesity Forum, said gadgets were taking their toll on the well-being of youngsters.

He said: "Adolescents are now slaves to handheld devices and this is doing nothing for their health.

"Incredibly, teenagers believe that playing computer games with their friends from the privacy of their bedrooms is a form of physical activity and rebel if grounded from their Facebooks or Instagrams."

The report covering 42 countries, including Russia, Ukraine, Iceland and Israel, found that while the time young people spent watching television had steadily declined across Europe they were increasingly going online instead.

In 2002, only 15 per cent of European girls, aged 15, and around 35 per cent of boys the same age spent at least two hours a day during the week using computers for non-gaming activities. By 2014, that had surged to 65 and almost 75 per cent respectively.

The report states: "These results imply that daily habitual physical activity (such as walking, cycling and active play) has largely disappeared from adolescents’ lives in most countries and regions across Europe. At the same time, computer use for gaming and non-gaming purposes has increased sharply and offsets the substantial declines in TV-watching in terms of time use ...

"The current guideline of less than two hours of recreational screen time is therefore being met only by a minority of European adolescents. These trends are alarming in relation to obesity prevention."

While the same report also found evidence of an "encouraging" decline in the consumption of sweets and sugary soft drinks in the UK as a whole, one in three Scottish teenagers still eat sweets or chocolates every day. This compares to a quarter of teenagers in England and Wales.

However, Scotland recorded one of the sharpest drops in consumption of sugary drinks. In 2002, nearly half of Scots youngsters said they had high-calorie soft drinks every day, but by 2014 that was down to less than a quarter.

In England, the figure dropped from 38 per cent to 13 per cent over the same period. Only Ireland, Israel, and Slovenia experienced similar decreases.

Dr Inchley said: "Within the UK, we found an overall decline in the consumption of sweets and sugary soft drinks, which is encouraging, but a third of Scottish adolescents still eat sweets or chocolates every day, compared to a quarter of adolescents in England and Wales.

"The reductions in consumption of sugary drinks amongst young people in Scotland is good news, however, further action is required to reduce their sugar intake, particularly in light of the wide range of sugar-sweetened drinks now available and actively marketed to children and adolescents."