Sydney, Mar 19 (IANS): Nagging negative thoughts - and striving for perfection - keep teenagers awake at night, raising their chance of becoming depressed and anxious, say researchers.

An online study of almost 400 adolescents aged 14 to 20 years confirmed the link, leading researchers at Flinders University in Australia, to recommend alternative treatments for repetitive negative thinking and perfectionism in dealing with delayed sleep and mental health problems among teenagers.

The study, published in the journal Sleep Health,confirmed a link between repeated negative thinking and delayed sleep.

"Repetitive negative thinking is habit forming and it can significantly contribute to making sleep difficult and causing depressed mood in teenagers, who already like to stay up late at night," said study researcher Michael Gradisar, Professor at Flinders University in Australia.

"This study supports the need to recognise repetitive negative thinking in preventing and treating sleep problems, along with individual differences in perfectionism and mood," Gradisar added.

According to the researchers, the role of repetitive negative thinking and perfectionism in explaining the link between sleep onset problems and depressed mood has important clinical implications through providing possible treatment targets.

International studies indicates depression affects between three per cent and eigh per cent of adolescents. It is often recurring and may continue to develop into more severe depressive disorders during adulthood.

In teenagers, depression can cause poor concentration, a loss of interest in schoolwork, difficulties in peer relationships, and even suicide, the researchers said.

The researchers stresses that sleep plays an important part in preventing and treating depression in teenagers.

Parents and carers can implement better sleep health by encouraging regular bedtime routines during the school week and weekends, and encouraging mobile phones to be turned off earlier in the evening, according to the study.

According to the researchers, busy lifestyles, stress and screen time makes self-help and accessible resources for better sleep increasingly important.