These disturbances to the body's internal clock, characterised by 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.
This study is the first to objectively measure patterns of rest and activity (using accelerometers), and to have sufficient sample size to assess the effect of circadian disruption on various mental health disorders.
The researchers also adjusted for a wide range of factors including age, sex, lifestyle, education, body mass index, and childhood trauma.
Disruption of the body's internal clock linked with mood disorders and adverse wellbeing [press release]. "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".
Body clock rhythms govern fundamental physiological and behavioural functions - from body temperatures to eating habits - in nearly all living beings.
Although previous research has identified associations between disruptions in circadian rhythm and poor mental health, these studies typically had small sample sizes, were based on self-reports, or adjusted for few potential confounders. Greater disease risks arising from circadian disruption have been identified in the brain, pancreas, and stress systems.
For the new study, an global team led by University of Glasgow psychologist Laura Lyall analyzed data - taken from the UK Biobank, one of the most complete long-term health surveys ever done - on 91,105 people aged 37 to 73.
To record their levels of activity, participants wore accelerometers for 7 days between 2013 and 2015. It was also associated with greater mood instability (OR, 1.02; 95% CI 1.01-1.04), higher neuroticism scores (incident rate ratio, 1.01; 95% CI 1.01-1.02), more subjective loneliness (OR, 1.09; 95% CI, 1.07-1.11), lower happiness (OR, 0.91; 95% CI, 0.90-0.93), lower health satisfaction (OR, 0.90; 95% CI, 0.89-0.91), and slower reaction times (linear regression coefficient, 1.75; 95% CI, 1.05-2.45).
Mathematical modelling was used to investigate associations between low relative amplitude (reflecting greater activity during rest periods and/or daytime inactivity) and lifetime risk of mood disorder as well as wellbeing and cognitive function. Association of disrupted circadian rhythmicity with mood disorders, subjective wellbeing, and cognitive function: a cross-sectional study of 91 105 participants from the UK Biobank [published online May 15, 2018].
People with the lower relative amplitude were at higher risk of mental health problems such as anxiety, depression and bipolar disorder.
People who fail to follow their natural body clock rhythm are more likely to have depression and mental health problems, a study has found.
He added: "The circadian system undergoes developmental changes during adolescence, which is also a common time for the onset of mood disorders".
The study was funded by the Lister Institute of Preventive Medicine.