Lower relative amplitude was also found to be reliably associated with greater mood instability, higher neuroticism scores, more subjective loneliness, lower happiness and health satisfaction, and slower reaction time (an indirect measure of cognitive function).
"To look at this in more detail, it will be useful for future studies to track participants' rest-activity patterns over time to see whether disturbed rhythms can predict whether someone is more likely to go on to develop a mood disorder", commented author Dr Laura Lyall from the University of Glasgow.
Regarding the study, he said: 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 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.
"But it's not just what you do at night", he said, "it's what you do during the day - trying to be active during the day and inactive in darkness", he told.
Those with a lower amplitude were found to be at higher risk of mental issues, even when factors such as age, sex, smoking status, educational attainment and childhood trauma were taken into account.
The researchers used activity data on 91,105 participants in the UK Biobank cohort to obtain an objective measure of daily rest-activity rhythms, called relative amplitude.
They were also more likely to feel lonely and less happy.
For those who struggle to maintain a consistent circadian rhythm, certain strategies - such as avoiding technology at night - have proven to be an important part of good sleep hygiene.
Previous research has identified associations between circadian disruption and poor mental health, but these were typically based on self reports of activity and sleeping patterns, had small sample sizes, or adjusted for few potential confounders. "I don't think it's unreasonable to say this is another piece of evidence that might suggest we should all be more mindful of our natural rhythms of activity and rest", Professor Smith explained.
The findings have significant public health consequences, particularly for those who live in urban areas, where circadian rhythms are often disrupted due to artificial light, according to Smith.