Paris Jackson -- Facebook Has Destroyed Her

Paris Jackson's deep depression has been largely the result of bullying ... and Facebook has been hosting the haters.

Sources closely connected to Paris tell TMZ ... the 15-year-old has been reeling from comments left on her Facebook page --- many about Michael Jackson and his lifestyle. Some of the comments involve the various molestation allegations ... others involve the odd life Paris lived while Michael was alive.

We're told Paris has taken the comments very personally ... and one source says, "They destroyed her." The source adds, there's a nexus between the bullying and her penchant for cutting.

Now here's the problem. Paris does not have access to her Facebook page while she's in the psych ward at UCLA Medical Center. But her family is deeply concerned that she'll backslide if she goes back on Facebook when she gets out.

The family is extremely frustrated, because they've tried to shut down Paris' Facebook page, but they can't --- Facebook's policy is that the family of a user has no right to shut down an account if the user is 13 years of age or older.

Paris' family believes Facebook could create yet another tragedy in the Jackson family, but they're powerless to do anything about it.