I think some of the sources like the Reviews.org survey, JAMA analysis and Sleep Medicine study have flaws and are largely correlational, not causal. The Reviews.org data is self reported, not peer reviewed or randomised, and probably has sampling bias. JAMA's analysis is observational, so it doesn't prove causation. The Sleep Medicine study uses a tiny sample, short duration, and likely has self selection bias.

Regardless, we all sense that excessive smartphone use ties to lower mood and higher depression risks. There's already an influx of people experimenting with timers, dumbphones, or just switching their phone off, but app builders will keep chasing our attention no matter what. It's their core business. As the patchy research (in both quantity and quality) shows, real change won't come until we as a society dig deeper into the problem.

key points that stood out to me:

- Smartphones are built to addict via dopamine from notifications and scrolling. Americans check theirs 144 times a day on average. Strong links to anxiety, depression, poor sleep, and weaker focus.

- Short breaks (24 hours to a week) can boost focus and mood. Limiting non work screen time to under two hours daily correlates with lower depression.