The relationship between sleep and mental health is well recognised, and a lack of sleep is known to aggravate most psychological disorders. Although it’s still unclear as to whether sleep disruptions are caused by mental health issues or if they’re a symptom of them, a new study has confirmed that there is a strong connection between the two. In the largest study to date, with data collected from around 500,000 participants, scientists have found that those who have disrupted sleep cycles are more likely to suffer from mood disorders, feelings of loneliness and have lower happiness levels.
For the study, the scientists looked at patterns in the participants 24 hour sleep cycles and in their activity. Their circadian rhythms, which a range of functions including sleep patterns and the release of hormones, were examined to measure their relative amplitude. They found that those with lower relative amplitude were at an increased risk of suffering from mental health problems including depression and bipolar disorder. They were also more likely to suffer from feelings of loneliness, and reported lower levels of happiness overall.
“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?” said Daniel Smith, professor of psychiatry at the University of Glasgow and lead author of the research.
He added: “What that tells us is about the inconsistency or the disruption in the regularity of the routine of rest and activity. People who are active during the day and sleep well at night, that is a very healthy profile … they would have a high score in relative amplitude. Whereas people who tend to be disturbed in their sleep, are up a couple of times in the night and conversely tend to be not very active during the day, they score low in relative amplitude. 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.”