Occasionally I hear my friends who have psychological disorders complain that healthy people don't understand what they feel. Therefore they prefer to be supported by someone who also has psychological disorders, because they can understand each others. This and other relevant beliefs constitute what I would call "belief system of people with psychological disorders".
I would like to study more about this belief system, and the dynamics of a relationship (friendship, romantic relationship, parent-child relationship, etc) when there are differences in beliefs, expectations, experiences, and personalities, etc. Especially when one of them is healthy and the other one is not (psychologically or physiologically). What would people react with such contradictions, what forces them to react such way, and how will that solve problems or make situations worse (e.g. get misunderstanding and hurt)? Do you have any pointers?