Some 74% of girls who received their first smartphone at age six said they felt distressed or were struggling, the study found.
This decreased to 52% for those who got their first smartphone at age 15.
Meanwhile, 42% of boys who got their first smartphone at age 6 experienced feeling distressed or struggling, and this reduced to 36% for those who received a smartphone at age 18.
"Social media, we suggest delaying until 16, so a little older."
Some academics and scientists remain unconvinced of a causal link between smartphones and poor mental health, however.
Persons:
Zach Rausch, Jonathon Haidt's, Rausch, Christopher Ferguson
Organizations:
Research, New York University Stern School of Business, New York Times, CNBC
Locations:
preteens, U.S