Social media can be harmful. I don't think as many people get addicted to blogs as social media. Real "face to face personal relationships" with people are hands down better than either blogs or social media. I don't think that would be disputed.
A University did a study last year on social media's effect on self esteem and anxiety and reported that 50% of the 298 participants said "that their use of social networks, like Twitter, Instagram, and Facebook, made their lives worse". Research shows that they had a false sense of belonging and connecting that wasn't real world based. One big reason for this is that all those "assumed connections" that people are checking in on out of habit, several times a day, look like they are having the perfect life. It just often isn't real and if your life isn't perfect it can be depressing. People can be whoever they want to be on those sites. Whatever they are doing, it can be a staged situation, not a shared life. Our lives can look boring in comparison. As said it can lead to a lot of stress and anxiety. Not good things. Other peoples passions can be polarizing.
Depression, in part, is a state of not caring. The world turns "black and cold" all around us when were depressed. Things just don't matter. Anxiety may be the other end of this same spectrum. On that side you care "far to much about everything" and there is no way to accomplish all that you care about.
Connecting with people can help for either problem. Getting "out of ourselves" helps. People, books, art, poetry, service, our ancestors, and music can all help us get out of ourselves. If it is people that are going to pull us out they need to be pulling us into the real world not a made up fantasy on line reality show.
Having said this I have to acknowledge the real world. I may wind up using these same social media sites as places to offer some very short encouragement and to try to pull people to this site. I don't think I originated any of this so I hope you don't want to hang the messenger