Sleepless nights blamed for rise in teen depression 

Young people who become sleep deprived by using the internet into the small hours are much more likely to become mentally ill in later life, research shows.

Lack of sleep may help explain the puzzling increase in mental illness among young people in recent decades, according to an extensive study.

And regularly staying up late to surf the internet and chat on social networking sites could be one reason young people are sleeping less, according to the research. 

Night-owls: Young people who become sleep deprived because of late night internet use are more likely to become mentally ill

The study of about 20,000 young people aged between 17 and 24 found that those who slept fewer than five hours a night were three times more likely than normal sleepers to become psychologically distressed in the next year.

Each hour of sleep lost was linked to a 14 per cent increased risk of distress, according to the results, published in the journal Sleep. 

Professor Nicholas Glozier, who led the research, said: 'Sleep disturbance and in particular insomnia is a predictor of later development of depression and possibly anxiety.'

Less sleep was also associated with longer-term mental health problems - which were the focus of the professor's study.

A lot of mental ill-health comes and goes, he said. 'It's the ones who don't get better that we are particularly interested in.'

The professor, who researches psychiatry and sleep medicine at the University of Sydney, believes lack of sleep could contribute to increasing rates of depression. 

He said: 'Large numbers of my patients are on Facebook or the internet or massive multiplayer games until one or two in the morning but are having to get up at 7am.

'Older people and people in middle age have been sleeping longer but young people have not.' 

Sleep problems and mental-illness could exacerbate each other, the expert added.

'Many of these kids could have sleep problems as a result of previous disturbances,' he said.

'But what we are seeing are young adults who tend to start off with anxiety and body-clock problems and move on to problems like bipolar or major depression.' 

Lack of sleep: Researchers found those people who got less than five hours sleep a night were three times for likely to be psychologically distressed

The amount of time people spend online, especially young people, has been rising in recent years and fuelled in part by the growth of social networking sites.

Recent figures showed that, on average, internet users in the UK are spending more than six hours each month on sites such as Facebook and Twitter.

Australia has the highest average use on such sites, at seven hours a month. 

Professor Glozier, with researchers from Sydney's-Woolcock Institute and the Brain and Mind Research Institute, is pioneering methods to correct the body clocks of sleepdeprived people to assist their mental health.

'Their body-clocks are naturally out of kilter with the rest of society and some of them this really impacts on,' he said.

Patients are treated with light therapy in the mornings as well as hormones such as melatonin to help them sleep earlier.

The Australian study is the latest to highlight sleeping problems.

Research published this week in the American Journal of Obstetrics and Gynaecology, found new mothers were not getting the right quality of sleep because they were constantly being woken.

Separate research in the U.S. revealed that men who suffer from insomnia are at risk of dying younger. 

Male insomniacs are far more likely to die prematurely than men who get a regular night's sleep or female insomniacs, the Penn State study found.