A smartphone, when operating, is a small, backlit screen. Let’s start with “backlit” part. You’ve probably read that phones emit blue light. We have lots of scientific research about the effect of blue light on the circadian rhythms that are an important part of human sleep. Blue light is particularly effective at suppressing the secretion of the sleep-aid hormone melatonin. As almost anyone knows, good sleep improves hormonal regulation across the board, and with it, mood and outlook.

But it’s not just the backlit nature of the screen that’s messing with our hormones. It’s also the relatively tiny size and vertical plane of it. First of all, a small screen in the hand often changes our posture. Staring into a cell phone for hours a day can feel like flying coach from San Francisco to Sydney, Australia — you spend lots of time with your shoulders falling forward, hunched over with a sunken chest, and a head tilted downward. This posture dramatically increases the release of stress hormones. It can also lower oxygenation and activate subtle and not-so-subtle fight-or-flight responses. Using our phones often causes us to literally take on the posture — and subsequently the hormonal dysregulations — of a depressed and fearful person.

Maybe it’s making us worse people, too. One study found that hard-core online gamers showed gray-matter atrophy in the right orbitofrontal cortex, bilateral insula, and right supplementary-motor areas of the brain. These parts of the brain are related to impulse control, planning, organization, and even compassion. As social media have become “gamified,” maybe we all lose some impulse control and the ability to sympathize. There are studies on how focused attention to a task — being in the zone — helps to regulate our emotions and to give us a sense of well-being and accomplishment. Self-induced attention-deficit disorder would seem to disrupt that well-being.