Is this the personal statement for the first application or the secondaries? In my application to AACOM I listed why I was interested in Osteopathic medicine. In the secondaries each school might ask something different. Some schools ask why you want to be an osteopathic physician. Others ask what qualities can you bring to the school. But I would include why you want to be an osteopathic physician in every essay you write.
I have a question with reguard to the personal statement (right now, I am considering both MD and DO). What type of stuff are the adcoms looking in a personal statement which asks why one is interested in medicine. I have my personal reasons, but I feel that they might be inadequate for the adcom. I know that I am not old enough to think about these issues (I start the baccalaureate degree phase in 3 weeks), but I have to think about what I will write.
The personal statement is a great time to explain in detail why you want to go into medicine. It sounds like you have some ideas/reasons for wanting to pursue a career as a physician. Take those ideas, and spend the next 4 years exploring them.
Let me give an example... Do you enjoy working with people? Spend some time volunteering in a hospital, or a nursing home, or a daycare... Interact with people and enjoy yourself. When you get to the personal statement you can say, I enjoy intereacting with people and my time volunteering at the hospital really opened my eyes to how much I'd like to work with people in medicine.
Is your interest that of your love of science? Get involved with some biomedical research at school. Explore the ideas... Then you have "evidence" that you really do enjoy science and research.
I could go on forever. I think it is very important to present yourself as a well rounded applicant. If you have reasons for wanting to be a doctor, go explore facets of them and enjoy them. Not only will it better prepare you for medical school, but you will enjoy yourself in the process.