It all depends on person. I have smartphone and I use it a lot in my work and everyday life. But when I'm with my family or friends I can live without it for few hours. I even leave it sometimes when I go out for a few minutes or walk my dog. You jusy have to balance your online and offline life and not give in to the extremities.
Yes, it all depends on how people use it. I can safely do jogging or walking in the open air a few ches without a smartphone and this does not cause me depression or discomfort.