I came across this on Slashdot (the original article was on Bloomberg):
Brain scans of adolescents who are heavy users of smartphones, tablets and video games look different from those of less active screen users, preliminary results from an ongoing study funded by the National Institutes of Health show, according to a report on Sunday by "60 Minutes." That's the finding of the first batch of scans of 4,500 nine- to 10-year-olds. Scientists will follow those children and thousands more for a decade to see how childhood experiences, including the use of digital devices, affect their brains, emotional development and mental health.
In the first round of testing, the scans of children who reported daily screen usage of more than seven hours showed premature thinning of the brain cortex, the outermost layer that processes information from the physical world.... Early results from the $300 million study, called Adolescent Brain Cognitive Development (ABCD), have determined that children who spend more than two hours of daily screen time score lower on thinking and language tests. A major data release is scheduled for early 2019.
It sounds like that’s quite a major effect, I’m really interested in how the results will turn out, and also what if anything the implications will be for adult screen time. Scary! But also surprising that it has taken them this long to organise a major study, after all video games and handheld consoles have been around since the early 1990’s at least. Doing this in the smartphone era sounds like closing the barn door after the horse has bolted...