Body clock disruption linked to depression

People who have disrupted sleep cycles have “lower levels of happiness and greater feelings of loneliness”, new research suggests.

In the largest study of its type, researchers at the University of Glasgow asked more than 90,000 subjects to wear activity monitors for a week in order to monitor disruption to their biological clocks, or circadian rhythm. If the participants was highly active at late hours, or inactive during the day, this was classed as a disruption, Business Insider reports.

The scientists found that people who experienced more circadian disruption were between 6% and 10% more likely to have been diagnosed with a mood disorder than people who had more typical sleep cycles. Irregular sleep patterns were also associated with mood swings and increased neuroticism and feelings of loneliness and unhappiness, along with slower reaction times.

Daniel Smith, a professor of psychiatry and the lead author of the research paper, published in The Lancet Psychiatry, said: “Because people have these 24-hour patterns of living nowadays, and because by 2050 two-thirds of the world’s population will live in cities, where circadian disruption is much more likely, it is quite a big public health issue.

“How do we take account of our natural patterns of rest and activity and how do we design cities or jobs to protect people’s mental health?

“The next step will be to identify the mechanisms by which genetic and environmental causes of circadian disruption interact to increase an individual’s risk of depression and bipolar disorder. This is important globally because more and more people are living in urban environments that are known to increase risk of circadian disruption and, by extension, adverse mental health outcomes.”