Screen time has little effect on the psychological wellbeing of teenagers, regardless of whether they use devices for hours a day or just before bedtime, according to a study by researchers at Oxford University.

The research, based on analysis of the screen use of more than 17,000 teenagers across Ireland, the US and the UK, found use of screens before bedtime was completely unrelated to psychological wellbeing, and screen time more generally had a “minuscule” effect on wellbeing in teenagers when compared with other activities in an adolescent’s life.

The effect was believed to be small enough that adolescents “would need to report 63 hours and 31 minutes’ more of technology use a day in their time-use diaries to decrease their wellbeing” by an amount big enough for them to notice.

The study, published in the journal Psychological Science, is an important data point in the growing debate about whether excessive screen time can damage the mental health of young people.

Amy Orben, the lead researcher on the paper, said: “Because technologies are embedded in our social and professional lives, research concerning digital screen use and its effects on adolescent wellbeing is under increasing scrutiny.”

Orben and her co-author, Prof Andrew Przybylski, argue their approach improves on earlier “unreliable” studies based solely on self-reported screen usage, even though “only one-third of participants provide accurate judgments when asked about their weekly internet use … Heavy internet users tend to underestimate the amount of time they spend online, while infrequent users overreport this behaviour.”

Instead, the researchers combined time-use diaries and self-reported measures to come up with a more accurate record of how much time the thousands of participants spent using digital technology. They also adopted best practices from medical research, such as study pre-registration, to guard against the possibility of tweaking the statistics in order to secure more compelling results.

The research was welcomed by others in the field. Dr Max Davie, an officer for health improvement for the Royal College of Paediatrics and Child Health, said: “The controversy around screen use and adolescent wellbeing has always suffered from an excess of opinion relative to data, and this paper helps to correct this imbalance.

“The analysis is robust and suggests an overall population effect too small to warrant consideration as a public health problem. They also question the widely held belief that screens before bedtime are especially bad for mental health.”

But Davie argued individuals can still suffer from excessive screen time, and noted “there are other reasons beside mental health for children to need a good night’s sleep”. For that reason, he recommended families continue to follow the RCPCH’s guidelines for screen time.

Those guidelines recommend parents set clear boundaries on screen use, both for themselves and their children, and prioritise face-to-face interaction over online friendships in order to set a good example for the family.

Dr Bernadka Dubicka, chair of the child and adolescent faculty at the Royal College of Psychiatrists, warned that the study’s conclusions “can only be limited.”

“The study looks at how long children spend looking at screens but not at what harmful content they might see. We know that screen time is not the main driver of mental illness, but dangerous online content can have an enormous impact on young people and their mental health.

“As a frontline clinician, I regularly see young people who have deliberately hurt themselves after discussing self-harm techniques on social media. Urgent research is needed to explore the complex relationship between online content and young people, with particular attention given to the most vulnerable.”