Excess use of smartphone and other devices may lead to attention, behaviour and self-regulation problems for adolescents already at risk for mental health issues, warns new research.

"Also, on days at-risk adolescents use technology more, they experience more conduct problems and higher ADHD (attention-deficit/hyperactivity disorder) symptoms compared to days they use technology less," said lead author of the study Madeleine George from Duke University in Durham, North Carolina, US. The research, published in the journal Child Development, looked at associations between adolescents' mental health symptoms and how much time they spent each day texting, using social media and using the internet.

For the study, 151 young adolescents completed surveys on smartphones about their daily digital technology use.They were surveyed three times a day for a month and were assessed for mental health symptoms 18 months later. The youth participating were between 11 and 15 years old.The adolescents spent an average of 2.3 hours a day using digital technologies. The researchers found that on days when adolescents used their devices more -- both when they exceeded their own normal use and when they exceeded average use by their peers -- they were more likely to experience conduct problems such as lying, fighting and other behavioural problems.In addition, on days when adolescents used digital devices more, they had difficulty paying attention and exhibited attention deficit-hyperactivity disorder symptoms. The study also found that young adolescents who spent more time online experienced increases in conduct problems and problems with self-regulation -- the ability to control one's behavior and emotions -- 18 months later.

However, the study also found that using technology was linked to some positive outcomes. On days when adolescents spent more time using digital technologies they were less likely to report symptoms of depression and anxiety.