Tick tock Study links body clock to mood disorders

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AFP
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Messing with the natural rhythm of one's internal clock may boost the risk of developing mood problems ranging from garden-variety loneliness to severe depression and bipolar disorder, researchers say. Photo: AFP 
 

PARIS: Messing with the natural rhythm of one's internal clock may boost the risk of developing mood problems ranging from garden-variety loneliness to severe depression and bipolar disorder, researchers said Wednesday.

The largest study of its kind, involving more than 91,000 people, also linked interference with the body's "circadian rhythm" to a decline in cognitive functions such as memory and attention span.

The brain's hard-wired circadian timekeeper governs day-night cycles, influencing sleep patterns, the release of hormones and even body temperature.

Earlier, research had suggested that disrupting these rhythms can adversely affect mental health, but was inconclusive: most data was self-reported, participant groups were small, and potentially data-skewing factors were not ruled out.

For the new study, an international team led by University of Glasgow psychologist Laura Lyall analysed 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. The volunteers wore accelerometers that measured patterns of rest and activity and had this record compared to their mental history, also taken from the UK Biobank.

Individuals with a history of disrupting their body's natural rhythm -- working night shifts, for example, or suffering repeated jetlag -- also tended to have a higher lifetime risk of mood disorders, feelings of unhappiness, and cognitive problems, the researchers found.