The study was published earlier this week in the peer-reviewed Journal of Human Development and Capabilities, and found that 18- to 24-year-olds who had received their first smartphone at age 12 or younger were more likely to report suicidal thoughts, aggression, detachment from reality, poorer emotional regulation, and low self-worth.

OECD data in 2018 showed that New Zealand youth used digital devices 42 hours per week on average, compared to 35 hours globally, and studies have shown that children's screen use has increased since then.

So how can parents and caregivers manage screen time?

Kathryn speaks with Jackie Riach, psychologist and country lead for Triple P New Zealand which provides parenting programmes nationwide.

Go to this episode on rnz.co.nz for more details