“Do you wonder why mental health of teenagers plunged in the in the early 2010s (e.g., increase in anxiety, depression, suicidal thoughts) with a decrease in actual social interactions (e.g., dating or leaving home to live independently)? I was aware of, and have done research on, the negative impact of smartphones and other screens such as the hours of scrolling social media, gaming, texting, watching streaming videos or user generated videos on Instagram, TicTok, YouTube. When decreasing phone use, health, well-being and productivity often improves. Illustrated by the report of a 23-year male student who choose to reduce his smartphone use from more than 7 hours to three hours per day for five weeks as part of a class project.”