Does depression lead to cellphone addiction, or vice versa?

In another classic "chicken-or-the-egg" type of conundrum, a newly released study is claiming that instead of a so-called "cellphone addiction" causing people depression and lower self-esteem, as we'd previously heard, the supposed addiction may actually be triggered by those very same negative feelings. In a study of school-aged South Korean children, Dr. Jee Hyan Ha found that those students who used their phones the most (90 or more times a day, including SMS) also tended to score higher on a psychological test intended to measure a person's level of depression. Although none of the students' scores reached the level of clinical depression, the heaviest users were observed to have significantly more self-identity issues than average, suggesting to researchers that communicating via cellphone made the "addicts" feel popular. So which is it: does heavy cellphone use lead to depression, or does depression lead to heavy cellphone use -- or is it just a vicious cycle with no end and no beginning?

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