Your Body Clock is Associated With Mood Disorders

Wednesday, 16 May, 2018

It found that increased activity during rest periods and/or inactivity during the day are also associated with mood instability, more subjective loneliness, lower happiness and health satisfaction, and worse cognitive function.

Dr Laura Lyall, the study's lead author, said the team had found a robust association between disruption of circadian rhythms and mood disorders.

Measurements of people's rest-work cycles could be a useful tool for flagging and treating people at risk of major depression or bipolar disorders, the researchers concluded.

Where did the story come from?

Based on the observational nature of the study, the researchers were unable to show causality, meaning it is unclear whether the sleep disturbances caused the mental health problems or vice versa.

The study was widely covered in the United Kingdom media.

"It's an exciting time for this kind of research because it's beginning to have some real-world applications", Smith said.

While studies like this can spot patterns of connections between factors, they can't tell us whether one factor (such as activity cycles) actually causes another (such as depression). They occur in plants, animals and throughout biology, and are fundamental for maintaining health in humans, particularly mental health and wellbeing.

Using the activity monitors, the researchers calculated people's day/night activity levels - a measure which shows the ratio between someone's activity during their 10 most active hours and their 5 least active hours. "However, these are observational associations and can not tell us whether mood disorders and reduced wellbeing cause disturbed rest-activity patterns, or whether disturbed circadian rhythmicity makes people vulnerable to mood disorders and poorer wellbeing". The disruptions were measured by an accelerometer worn on the subjects' wrists, tracking their levels of activity daily.

What were the basic results?

It was also associated with greater mood instability, higher neuroticism scores, more subjective loneliness, lower happiness and health satisfaction, and slower reaction time. In other words, the findings can not determine whether it was the disrupted internal clock which caused the mood disorder or vice versa.

They also said the findings "cannot speak to the issue of causal associations" because of its cross-sectional nature, and that future work following up participants is needed.

"It's widely known that a good night's sleep is a good thing for well-being and health".

He added it is advisable to avoid activities that disturb the circadian rhythm after 10pm, but that activities during the day were just as important, giving the example of being outside in the morning during the winter months.

"So we need to think about ways to help people tune in to their natural rhythms of activity and sleeping more effectively".

Smith said, '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.

Sleep hygiene - such as turning off screens before bed time and ensuring the bedroom is quiet, dark and cool - can help.