Are students addicted to their phone ? Is it a problem?

I feel that i'm not sure if students are addicted to their phones. Because some of people doesn't have a phone and they focusing to their school work and family but I do agree that some of people are addicted to their phone. For example some people that i know is more interested in reading books and  i know some people are kinda addicted to their phone because they always use it during class some of them got caught, but they're still doing it and the last example is people do listen to their music every so i'm not sure if that is addiction or not . This is why i feel that i'm not sure.