According to the Los Angeles Times
A survey of 575 high school student in the United States showed that two-thirds of the students who use their cell phones more than 90 times a day do so because they are unhappy or bored. they score higher on tests that measure depression and anxiety compared to students who use their phones less. However, when they were examined, the frequent users were not found to be clinically depressed .. That is, they were not actually in a state of depression that was severe enough to require medical help. The researcher who conducted the study said, "The young people may be unhappy because of a problem in their lives or anxious about their social status.
They are trying to make themselves feel better by reaching out to others. Communicating via cell phone makes the 'addicts' feel popular.