PITTSBURGH, June 23, 2025 – In this digital era, both kids and adults are often glued to smartphone screens. Digital technology keeps users entertained, connected to friends, and in tune with important news. But some reports suggest that, particularly for adolescents, excessive time on these screens can be linked to mental health problems and even depression.
New research from the University of Pittsburgh School of Medicine published today in JAMA Pediatrics suggests that that association is driven by shorter sleep and worse organization of the brain white matter during this crucial adolescent phase of brain development.
"Brain white matter connections are just like highways that connect cities," said lead author Dr. João Paulo Lima Santos, M.D., research instructor in psychiatry at Pitt. "If these highways are not well-maintained, traveling from one city to another can be slow and inefficient, or even disrupted."
In the study, researchers analyzed over 1,000 surveys where teens were asked to estimate how much time they spend per day looking at screens and how long they sleep each night, on average.
Participants' brain scans revealed something intriguing: white matter connections between regions of the brain that control emotion regulation, memory and attention were weaker and more disorganized in teens who spent more time on their phone or tablet and did not get sufficient sleep – more like meandering paths through a forest than an eight-lane speedway. Those teens also had higher depression scores, suggesting that the intersection of screen time and sleep quality might hold the key to better brain function and mental health.
"Our study considered digital screen time as a broad definition but it's really important to look at the nuances," Lima Santos said. "Time of day when you are using your smartphone and what content you engage with matters."
In his future research, Lima Santos is planning to further disentangle the relationship between brain organization, sleep and screen use habits. By collecting screen use data directly from phones, he hopes to get more answers about whether specific time of day when teens look at screens matters. He suspects the hour before sleep might hold the answer – but more research is needed to back it up.
"Taking away all digital media is not the answer," Lima Santos cautions. "Digital media can be good – but in some situations, particularly when sleep is affected, we should be more careful and pay attention."
Other authors of this research are Adriane Soehner, Ph.D., Candice Biernesser, Ph.D., Cecile Ladouceur, Ph.D., and Amelia Versace, M.D., all of Pitt.
