If you are applying to several different schools using one generic statement will be easily recognized and just as easily dismissed. WHY _ because you will be seen as not making an effort sell yourself to this particular school, low effort equals low interest to admissions representatives. Remember the admission committee will likely view thousands of these statements from qualified candidates and they will spot a weakness, flaw or lack of attention to the process in a heartbeat. What you don't want to do is give this committee an easy excuse to dismiss your statement and application.
Stay Focused on your Theme. Before you begin your personal statement, decide what point or theme you want to get across. Make sure the entire essay revolves around that point by editing out any sentences that may lead the reader astray. Though you may be tempted to share a lot of different information about yourself in order to give the admissions committee a complete picture, it is more effective to highlight one revealing, important aspect. Pick something about yourself that you feel makes you stand out from the crowd and is related to your decision to become a physician.