Irish children are presenting to clinics with sleep deprivation and exhaustion due to over-use of their mobile phones, a leading child psychotherapist has warned.

Colman Noctor was speaking to the Sunday Tribune after two studies last week revealed that young people are becoming addicted to their mobile phones, resulting in stress, restlessness and lack of sleep.

This in turn is leading to poorer performance at school, and poorer emotional health, including a higher risk of developing ADHD, the studies found.

"We are definitely seeing kids who are exhausted and sleep deprived because of their mobile phones," Noctor told the Tribune.

"Some children have the phone with them beside their bed and are communicating with their pals all through the night. Their use of phones is not being regulated by parents at all."

Noctor also said that there is a danger of young people becoming paranoid and stressed from mobile phone communication, particularly from text messaging.

"It has to be remembered that there are no social cues in text messaging," he said. "For example, say a 15-year-old texts her friend to say that she has to cancel their cinema plans and her friend texts back to say 'that's fine'. Because there is no body language or voice inflection being used the 15-year-old has no way of knowing if her friend is really fine, or if she is annoyed. This can ... really snowball into something bigger."

Noctor said that there is an onus on parents to exert greater controls over their child's use of mobile phones. "Just because a child has a mobile doesn't mean he should have access to it around the clock," he said. "Parents need to moderate the amount of time that children have access to their phones."

The authors of one of the studies which was conducted at a Swedish university, found that adolescents who made more than 15 phone calls and sent more than 15 text messages a day, not only slept poorly but were also spending more time on their computers, drinking more alcohol and coffee, and were more likely to smoke than their less-phone-dependent peers.