It’s no secret that using your phone at before bed isn't really conducive to a good night’s sleep.
However, now a study of more than 91,000 people has found that scrolling through your Instagram and Twitter feeds from the comfort of your pillow in the wee hours could increase the likelihood of developing a number of psychological problems such as depression, bipolar disorder and neuroticism.
Late night phone-usage is just one of the disruptive behaviours pointed out by the researchers, who attributed the links to the aforementioned symptoms to body clock disturbance.
Previous research has shown the detrimental effects of interruptions to the body’s natural 24-hour cycle of the body - known as the circadian rhythm - as the result of shift work that requires employees to work through the night.
However, this study, published in The Lancet Psychiatry by professors at The University of Glasgow, is the first to monitor body clock disruption on such a large scale.
Participants aged 37 to 73 had their activity levels monitored by wrist-work accelerometers, which they wore for a seven day period, enabling researchers to measure the extent at which their circadian rhythmicity was disturbed during this time.
However, there were caveats to the findings, given that participants were only monitored for a week and were exclusively middle-aged and above.
The researchers also conducted cross-sectional examinations to measure participants’ psychological wellbeing and found that roughly one in 25 had unusual activity habits whereby they weren’t that much more active during the day than the night.
These people were 11 per cent more likely to have bipolar disorder and six per cent more likely to be battling depression, they found.
Plus, they also reported lower happiness levels and greater rates of loneliness.
Such people suffer from “very poor sleep hygiene”, said lead author Daniel Smith of the University of Glasgow and would engage in late night activities such as playing on their mobile phones or making cups of tea.
The figures may seem small, however, Smith added they are no less significant:
“This is important because it seems to be across the board,” he said, “so it is a very consistent finding for these negative mental health and cognitive outcomes.”
While Smith advocated imposing a 10pm limit to phone usage to help combat this, he added that daytime activities have a part to play too, explaining that a healthy sleep pattern is often the result of being active during the day and inactive at night.
“I think this is important as a population health issue because so many of us are living with disrupted circadian rhythms,” he said.
“It’s unlikely that the way society is currently set up is good for your health. So many people are living in city environments flooded with light 24/7.”