Maintaining daily rhythm is important for mental health, study suggests – channel4000 gas house dance hall

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The study, published Tuesday in the journal The Lancet Psychiatry, looked at disruptions in the circadian rhythms — or daily sleep-wake cycles — of over 91,000 adults in the United Kingdom. It measured these disruptions using a device called an accelerometer that is worn on the wrist and measures one’s daily activity levels. The participants were taken from the UK Biobank, a large cohort of over half a million UK adults ages 37 to 73.

The researchers found that individuals with more circadian rhythm disruptions — defined as increased activity at night, decreased activity during the day or both — were significantly more likely to have symptoms consistent with bipolar disorder or major depression. They were also more likely to have decreased feelings of well-being and to have reduced cognitive functioning, based on a computer-generated reaction time test.

For all participants, activity levels were measured over a seven-day period in either 2013 or 2014, and mental health proxies such as mood and cognitive functioning were measured using an online mental health questionnaire that participants filled out in 2016 or 2017.

"It’s widely known that a good night’s sleep is a good thing for well-being and health. That’s not a big surprise," said Dr. Daniel Smith, professor of psychiatry at the University of Glasgow and a leading author on the study. "But I think what’s less well-known and what comes out of this work is that not only is a good night’s sleep important, but having a regular rhythm of being active in daylight and inactive in darkness over time is important for mental well-being."

Daily circadian rhythm is controlled by a collection of neurons in an area of the brain called the hypothalamus. The hypothalamus helps regulate a number of important behavioral and physiological functions such as body temperature, eating and drinking habits, emotional well-being and sleep, according to the National Institute of General Medical Sciences.

The findings are consistent with research indicating a link between sleep disruptions and mood disorders. A 2009 study, for example, showed that men who worked night shifts for four years or more were more likely to have anxiety and depression than those who work during the day.

"This study is the first large-scale investigation of the association of objectively measured circadian rhythmicity with various mental health, well-being, personality and cognitive outcomes, with an unprecedented sample size of more than 90 000 participants," Doherty wrote in an email.

"Previous studies have been very small (in just a few hundred people), or relied on self-report measures (asking people what they think they do). … However, this study used objective device-based measures in over 90,000 participants; and then linked this information to standard measures of mood disorders, subjective well-being, and cognitive function," he added.

"Not using your phone late at night and having a regular pattern of sleeping is really important," Smith said. "But equally important is a pattern of exposing yourself to sunshine and daylight in the morning and doing activity in the morning or midday so you can actually sleep properly."

"It’s a cross-sectional study, so we can’t say anything about cause and effect or what came first, the mood disorder or the circadian disruption," said Kristen Knutson, associate professor of neurology at Northwestern’s Feinberg School of Medicine, who was not involved in the study.

"The circadian system changes throughout life. If you’ve got kids, you know that very young kids tend to be nocturnal," Smith said. "My suspicion is that we might observe even more pronounced effects in younger samples, but that hasn’t been done yet, to my knowledge."

"It’s an exciting time for this kind of research because it’s beginning to have some real-world applications," Smith said. "And from my point of view as a psychiatrist, I think it’s probably under-recognized in psychiatry how important healthy circadian function is, but it’s an area that we’re trying to develop."