Disruption to the body clock increases the risk of mood disorders and depression, a large study has confirmed.

Scientists at the University of Glasgow looked at the circadian rhythms - which control functions including sleep patterns, body temperature, our immune systems and the release of hormones - of more than 90,000 people to measure daily rest-activity rhythms, called relative amplitude.

Individuals with lower relative amplitude were found to be at greater risk of several adverse mental health outcomes, even after adjusting for confounding factors, such as age, sex, lifestyle, education and previous childhood trauma.

Using mobile phones late at night or waking in the early hours to make a cup of tea were among the bad habits that contribute to "poor sleep hygiene", Daniel Smith, senior author of the paper, told The Times.

"But it's not just what you do at night, it's what you do during the day - trying to be active during the day and inactive in darkness," he said.