After numerous studies linking night shifts or varied schedules with a risk of obesity and diabetes, a new study suggests that people with such routines that disrupt sleep are more likely to develop mental health issues, including depression and anxiety than those with a nine-to-five job.
Shift workers have 28 per cent more chances of suffering from mental health problems than the people who have a nine-to-five job, as per data which has been examined from seven previous studies involving 28,438 participants.
The study by researchers at the University of Exeter in the UK suggested shift workers were 33 per cent more likely to have depression, in particular, than those who did not work at nights or had irregular schedules.
"Shift-work alters the circadian rhythm -- our normal sleep-wake cycle which matches the day-night cycle. The disruption can make people moody and irritable, and lead to social isolation as their time off matches family and friend's work and life commitments," lead author Luciana Torquati explained.
The study published in the American Journal of Public Health said that those who worked in shifts also had a higher risk of developing anxiety, but the difference was too small to rule out the possibility that it was due to varied shifts.
Women, in particular, appeared vulnerable, with 78 per cent more chances of experiencing adverse mental health outcomes, in shift work, said researchers, compared to females who worked consistent weekday schedules.
"It's possible that people with poor mental health wound up in jobs with irregular schedules, rather than developing mood disorders after they started working nights or inconsistent shifts," the findings suggested, highlighting the need for programs and policies to minimize shift workers' risk of poor mental health.
Depression accounts for 4.3 per cent of the global burden of disease, with mental disorders worldwide estimated to cost $16.3 million by 2030.
"The brain is programmed to sleep during night hours (absence of light) to recover from all the information processed during the day, while the daylight tells the brain it's time to be awake and process information," Torquati said, suggesting that workers and employees be aware of work schedule's potential impact on mental health.
Human beings' natural sleep cycle is controlled by a bundle of nerves in the hypothalamus called the suprachiasmatic nuclei (SCN).
The researcher added that limiting social isolation by finding time to exercise, going outside during daylight hours and spending time with family and friends may improve mood.
Another study suggested that between 10 and 40 percent of shift workers experienced Shift Work Sleep Disorder (SWSD), individuals with regularly shifting schedules most impacted, due to employee's non-traditional work hours.