The Phone in the Backpack

It starts with a quiet flicker. A fifth-grader, small for her age, sits at the back of a bus clutching a brand-new smartphone. Her parents had worried she’d be left out, that she’d miss birthday party group chats or struggle to find her friends after school. Now, as the bus bumps through traffic, she scrolls through a world she barely understands. Notifications explode like fireworks. Likes and messages—half kind, half cruel—compete for her attention. By the time she gets home, the phone will be more than an accessory. It will be a mirror, a megaphone, and a trap.

Research suggests she’s not alone—and she may already be on the wrong trajectory. Data from the Global Mind Project—nearly two million profiles collected across 163 countries—show a clear pattern: the younger a child is when they receive a smartphone, the more likely they are to struggle with mental health as a young adult. This isn’t about abstract “screen time.” It’s about measurable differences in how the human mind develops when digital immersion begins too soon.

The numbers are hard to ignore. Young adults who received their first smartphone at age 13 score an average of 30 on the project’s Mind Health Quotient (MHQ). Those who got one at age five score just 1. That’s not a rounding error; it’s a chasm. Behind those averages are steep rises in suicidal thoughts, detachment from reality, poor emotional regulation, and a collapse in self-worth—especially among young women. Forty-eight percent of females who had smartphones at age five or six report suicidal thoughts by age 24. The corresponding figure for those who got a phone at 13 is 28%.

The correlation doesn’t stop at symptoms. Early smartphone ownership is a near-perfect proxy for earlier exposure to algorithmically curated social media feeds, which account for roughly 40% of the negative outcomes measured. These feeds are engineered to capture attention, but they also mediate relationships, amplify social comparison, and funnel vulnerable users toward harmful content. Poor family relationships, cyber-bullying, and disrupted sleep—factors that used to be separable—are increasingly downstream of the same glowing rectangle.

The findings cut across continents, but English-speaking countries stand out. Children there tend to get smartphones and social media access earlier, and the consequences are sharper. In these regions, social media access explains up to 70% of the link between early smartphone use and later mind health problems. For young women, the data carry another grim footnote: sexual abuse linked to online contact accounts for 14% of the damage.

This is the point in the story where people usually ask for more proof, but the researchers behind the study argue the time for hedging is over. Tara Thiagarajan and her colleagues propose a precautionary principle. When children’s foundational emotional and cognitive capacities are at stake, they argue, waiting for perfect causal evidence isn’t responsible policy—it’s negligence.

Their recommendations read like a public health playbook. First, mandatory digital literacy programs for children before they’re allowed on social media—analogous to driver’s education before earning a license. Second, stronger enforcement of existing age restrictions, shifting the burden to technology companies with meaningful penalties for violations. Third, outright prohibition of social media access for children under 13, backed by robust verification systems. Finally, the hardest but most consequential step: delaying full smartphone access itself. Offer kids “dumb” phones that can call and text, but keep the algorithmic feeds out of their pockets until they’re developmentally ready.

This won’t be easy. Parents who withhold devices risk social ostracism for their children, and those children remain vulnerable to the downstream effects of their peers’ hyper-connected lives. Platforms profit from the youngest users and have little incentive to self-regulate. But the alternative is to allow what Thiagarajan calls

“a silent, population-level experiment”

to continue unchecked—a generation shaped by systems that prey on their developing neurology.

The image of the fifth-grader on the bus loops back in my mind. One device, one child, one choice made by loving parents trying to do the right thing. Multiply that scene by a few billion, and you start to understand why this isn’t just a private decision anymore. The question isn’t whether smartphones and social media are here to stay—they are. The question is whether we can delay children’s full entry into those digital worlds long enough for their minds to stand a fighting chance.