controlling purpose

My controlling purpose is to analyze the different causes of bulimia. I am doing this to figure out why, psychologically, people with the disorder have developed it. My controlling purpose and research questions are very similar in that they both look at the causes of the disorder. I do think I could more specific with my controlling purpose but I don’t want to say that just one thing is the exact cause of the disorder because I believe it’s kind of a clash of many things, and it is helping me answer my research question.