Young people today are far more likely to be depressed and to self-harm than they were 10 years ago, a new study suggests, as they struggle with body image and social media.

Researchers from University College London (UCL) and the University of Liverpool analysed data from two cohorts of 14-year-old millennials born a decade apart.

Fewer than one in 10 (9 per cent) of those born in the early 90s suffered from depression during their teens, but that rose to more one in seven for youngsters born at the turn of the century (15 per cent).

The children of the new century also tended to sleep fewer hours on week nights, were more likely to be obese and had poorer body image, compared to the children of the 1990s.

Rates of self-harm had also risen from 12 per cent to 14 per cent over the same period.

Worsening mental health in youngsters has coincided with the rise of social media as teenagers struggle to achieve the sort of perfection shown in photoshopped images on Instagram or Snapchat filters.

There are also worries that smartphones and iPhones in bedrooms are driving an increase in poor sleep.

Dr Praveetha Patalay, co-author of the study, said: “The increasing trends of poor sleep, obesity and negative body image might help explain rising mental health difficulties experienced by young people.