Sleeping against body clock is bad for mental health

People whose sleep pattern goes against their natural body clock are more likely to have depression and lower levels of wellbeing, according to a new study. The research, led by the University of Exeter, was published in the journal 'Molecular Psychiatry'.

The study also found the most robust evidence to date that being genetically programmed to be an early riser is protective against major depression, and improves wellbeing.

Researchers suggested this may be because society is set up to be more aligned to early risers, through the standard 9-5 working pattern. COVID-19 has led to more flexible working patterns and this research may help make the case for more adaptable working habits to suit individuals’ needs.

The team built on previous research which mapped 351 genes linked to being an early riser, or a night owl. They used a statistical process called Mendelian Randomisation to examine whether these genes were causally associated with seven mental health and wellbeing outcomes, including major depression, using data on more than 450,000 UK adults from UK Biobank’s biomedical database and research resource.

As well as the genetic information, participants also completed a questionnaire on whether they were a morning person or an evening person.

The team also developed a new measure of "social jetlag" that measures the variation in sleep patterns between work and free days. They measured this in more than 85,000 UK Biobank participants for whom sleep data was available, via wristworn activity monitors.

They found that people who were more misaligned from their natural body clock were more likely to report depression and anxiety and have lower well-being.

Lead author Jessica O’Loughlin, of the University of Exeter, said, “We found that people who were misaligned from their natural body clock were more likely to report depression, anxiety and have lower wellbeing. We also found the most robust evidence yet that being a morning person is protective of depression and improves wellbeing.”

O’Loughlin added, “We think this could be explained by the fact that the demands of society mean night owls are more likely to defy their natural body clocks, by having to wake up early for work.”