How is homelessness related to abnormal psychology?
I would assume it would be related to how and why you were homeless and what condition you are in while being homeless.
I am in no way an expert, but I do think I understand this.
Most people do not chose to become homeless, it is either caused by lack of money or job, or the excessive spending of money (alcoholic, drug addictions, etc.). Then it becomes psychological. The guilt, the rejection, the self-loathing of how and why you are in the situation can cause someone to slowly slip from their normal behaviors.
Not only is it a change made by you, but it is also from the environment. You no longer live in the same world as you once did. The people around you no longer look at you as human, but as a situation to keep away from. Food is harder to find and so is shelter, plus if you do have an addiction then money will also be a priority so you can have your fix. This leads to crimes or even more disgraces to your body and mind. Life is no longer pleasurable, but a test at survival.
However, it is not all this horrifying. Usually when you become homeless, the burdens of the rushing and electronic world around you falls away leaving a more natural life style. You no longer worry about bills, appearances, or luxuries. Although it isn't a devastating change like the ones mentioned before, it does change someone from who they once were. This is why the few who chose to be homeless or were forced to be but stayed, decided to do so.
The changes on the person's personality and brain process change drastically no matter how you look at it. To put it simpler, if you were to move or change schools, you would be affected by how you think of yourself (out of place, new start, strange place, etc.) and how the environment changes you (becoming shy, confident, broody, sad, etc.). I hope this helps and again I am no expert.