That article addresses the long term (lasting) of bullying.
There are two ugly outcomes that stem from learning to view yourself as a less than desirable, incapable individual. The first ugly outcome is that it becomes more likely that you will become increasingly susceptible to becoming depressed and/or angry and/or bitter. Being bullied teaches you that you are undesirable, that you are not safe in the world, and (when it is dished out by forces that are physically superior to yourself) that you are relatively powerless to defend yourself. When you are forced, again and again, to contemplate your relative lack of control over the bullying process, you are being set up for Learned Helplessness (e.g., where you come to believe that you can't do anything to change your ugly situation even if that isn't true), which in turn sets you up for hopelessness and depression.
At the same time, you may be learning that you are helpless and hopeless, you are also learning how you are seen by bullies, which is to say, you are learning that you are seen by others as weak, pathetic, and a loser. And, by virtue of the way that identity tends to work, you are being set up to believe that these things the bullies are saying about you are true.
It would be great if the average person was possessed of unshakable self-confidence, but this just isn't how identity works. Identity is a social process. Other people contribute to it. Particularly when people are young and have not yet survived a few of life's trials, it is difficult for people to know who they are and what they are made of. Much of what passes for identity in the young (and in the older too) is actually a kind of other-confidence, which is to say that many people's self-confidence is continually shored up by those around them telling them in both overt and subtle ways that they are good, worthy people. This is one of the reasons people like to belong to groups – it helps them to feel good about themselves. Bullying teaches people that they are explicitly not part of groups; that they are outcasts and outsiders. It is hard to doubt the reality of being an outcast and an outsider when you have been beaten or otherwise publicly humiliated. It takes an exceptionally confident (or otherwise well-supported) person to not internalize bullies' negative messages and begin bullying yourself by holding yourself to the same standards that bullies are applying to you and finding yourself a failure. In other words, it is rather easy for bullying victims to note that they have been beaten up and then to start thinking of themselves as weak, no-good, worthless, pathetic, and incompetent. These are the sorts of thoughts that lead to depression, or, if they are combined with revenge fantasies, to anger and rage feelings.
...the second ugly outcome unfolds more slowly over time. Having a wounded self-concept makes it harder for you to believe in yourself, and when you have difficulty believing in yourself, you will tend to have a harder time persevering through difficult situations and challenging circumstances. Deficits in academic performance can easily occur when bullying victims succumb to depression or otherwise become demoralized. They certainly also occur when victims ditch school to avoid bullies. The deficits themselves are not the real issue. The real issue is that if deficits occur for too long or become too pronounced, the affected children can lose out on opportunities for advancement and further study, and ultimately, employment. I've read retrospective studies where people report having left school early so as to avoid continued bullying, and this of course will have altered and limited the job prospects they have available to them as adults. Leaving school may be a dramatic (if occasionally realistic) example of how early bullying can affect one's life, but there are surely other ways that anger or depression caused by bullying harms and developmentally delays people's progress.
Walls of text, sorry, but they pretty much surmise what I've been positing in this thread for the last 4 pages.
