Sydney: Late night mobile phone use has devastating effects on teenagers' mental health, a study by Australian researchers at Murdoch and Griffith Universities said.
Funded by the Australian Research Council, the world's first long-term assessment of adolescent mental health regarding late night mobile phone usage examined students' quality of sleep, along with mood, aggression, coping skills, self esteem and whether they experienced any symptoms of depression, Xinhua news agency reported.
The process was conducted as an annual survey over four years and included 1,100 students from 29 schools.
When the subjects began the process, they were in Class 8 of High School. When the programme concluded, they had hit Class 11.
The questionnaires focused on what time of the night students continued to receive or send text messages and phone calls.
"We found that late night phone use directly contributed to poor sleep habits, which over time led to declines in overall wellbeing and mental health," lead researcher Lynette Vernon said.
"We have demonstrated how poor sleep is the key link connecting an increase in night-time mobile use with subsequent increases in psychosocial issues."
Around two thirds or 65 per cent of students in Class 8 who owned a mobile phone were reported to use it regularly after "lights out".
When the study concluded four years later, the figure was 78 per cent, finding that "as their levels of mobile phone use grew over time, so did their poor sleep behaviour", co-author Kathryn Modecki said.
According to Mark Levi, a Sydney-based sleep doctor, the scientific reason why mobile phones can have such a negative influence on sleeping patterns is due to the unnatural light they produce.
"Blue light in your bedroom retards your sleeping, it affects your hormones, it affects your melatonin secretions, your insulin secretions, it affects a lot of balance in the body," Levi told Xinhua on Tuesday.
"So the more you sit in bed and watch TV, play with your tablet, phone and have your phone beeping at 3 in the morning, all these things affect the slow waves of your sleep pattern and will give the person poor quality sleep.
"Blue light is a real, real problem in the bedroom. It's a big, huge problem."
For Levi, the findings of the study are no surprise, "there is no question, no question at all that it's a growing issue with teenagers, adolescents and the young", the sleep expert said.
"When a phone is beeping all night or they are watching a screen all night, it's affecting their sleep a lot and we're seeing child with sleep patterns that are disturbed and it's going to affect their attitude, their cognitive skills, concentrations skills, their moodiness during the day."
Despite the damning findings, Vernon said the answer to solving the problem was not to simply ban teenagers from using their devices but to find ways of promoting better sleep habits to adolescents.