The MD/PhD
A NextGen Pathways in Medicine Article
Although many students study science and even join research laboratories before medical school, as medical school students, many proceed to focus solely on clinical practice. Some, however, decide to devote their professional lives to both the clinic and the lab, and the many MD/PhD programs throughout the nation cater to these students, providing both the medical training available to MDs and the scientific rigor enjoyed by PhDs. While the MD/PhD study track poses substantial difficulties, physician-researchers with MD/PhD degrees may find that their additional training aids them in both facets of their professional lives, and that their careers are more rewarding than they would be with a single focus on either the clinic or the lab.
A Dual Education
According to the Association of American Medical Colleges, roughly 750 students matriculate in MD/PhD programs each year, a number that follows an increasing trend as additional medical schools begin offering dual programs. While females have historically been underrepresented in MD/PhD programs (there was a national 3:1 male to female ratio in 1991), they are steadily closing the gap (3:2 in 2005).
The Medical Science Training Program (MSTP) award, organized by the National Institute of General Medical Sciences (under the National Institutes of Health umbrella), provides grants for 45 institutions. The awards pay for the tuitions and stipends of over 900 currently enrolled MD/PhD candidates and distinguish the schools that receive the grant. Roughly $350 million are required every year for the cost of MD/PhD training at MSTP programs nationwide. 75 additional schools award MD/PhD degrees but do not receive funding from MSTP.
College graduates intending to pursue an MD/PhD degree often weigh and compare the track with the more traditional MD/residency/fellowship pathway. Physician-researchers in academia hail from both backgrounds, so the advantages of the MD/PhD program may seem dubious when a student following the traditional pathway can ultimately achieve the same professional goals. Ben Rapoport, an MD/PhD student at Harvard Medical School, explains that "the main prerequisite for doing good quality research is research experience, and many people would argue that whether that experience is obtained doing a PhD or during a fellowship may not make a critical difference."
The considerable time investment in education poses one of the largest disadvantages to pursuing an MD/PhD. The average course for MD/PhD students involves a total of seven to eight years, spanning a curriculum that merges a standard medical school education with graduate school coursework, lab rotations, and thesis research. By the time an MD/PhD student may have defended his dissertation, a medical school student would have already earned his MD degree, finished a fellowship in research, and completed most of his residency – which the MD/PhD graduate has yet to begin. The temporal gap between an MD/PhD and his peers may be quite discouraging. Richard Riese, a graduate of the MD/PhD program at the Medical College of Wisconsin, recalls, "Going through training in medicine during residency and fellowship, and during my years on staff at Brigham and Women's Hospital, I always felt somewhat behind my colleagues because of the time it took to complete my PhD degree."
However, for Rapoport, the time commitment is a necessary sacrifice gladly taken. "One undertakes the MD/PhD with an understanding that the added training will require additional years in school," Ben explains. He also recognizes the gap created with his medical classmates but does not regard it as "a problem in any way," considering it "fun and interesting to have friends and colleagues in different fields with different areas of expertise."
Having debated the direction of his future path as an undergraduate, Rapoport offers a number of advantages that come from pursuing an MD/PhD degree. Most superficially, "the PhD is a credential that certifies to the academic community that one has acquired a certain level of mastery in a particular field, and that in the judgment of its current intellectual leaders one is competent to perform research in that field up to a certain academic standard." For David Simon, an MD/PhD studying and practicing neurology at Beth Israel Deaconess Medical Center, this advantage may be even more practical. "It seems to take less time to start a research fellowship/post-doc after medical school," Simon says, "but then you need to do a longer post-doc before you are ready to start your own lab. If you do those extra years as part of a PhD degree program, then you get the extra degree, so it seems better to just get the degree."
According to Rapoport, a more significant advantage lies in the academic structure of an MD/PhD education. Enrolling as a graduate school student offers "coursework and other opportunities oriented toward students as developing investigators (internships, special seminars, and so on). Since clinical fellows are typically treated like postdoctoral research fellows, such opportunities are often not available to them." A formal graduate school education may provide a broader scientific base upon which advanced training would thrive. Pursuing the MD/PhD degree may also offer a more flexible program of study. Students at Harvard Medical School's MD/PhD program, for instance, have the option of studying the social sciences for their degree. The availability of additional resources and program flexibility allows a student to tailor his course of study to his scientific interests.
Finally, the MD/PhD program involves a strong mentorship with a research advisor. Says Rapoport, "I would venture to say that almost anyone who has pursued a PhD would agree that a good mentor is almost priceless. A PhD is often something like an apprenticeship, in which the mentor or principal investigator plays the role of master craftsman. A high-quality relationship with a research mentor is in my opinion the most important part of PhD training." Research advisors are expected to take responsibility for their students as apprentices, "explicitly conveying field-specific expertise and in terms of imparting less tangible skills required for an effective career in a particular area." Postdoctoral researchers, including MD graduates pursuing fellowships, are expected to have already had such experiences and are thus given more independence. They are therefore less likely to develop such an important mentorship relationship.
Post-Graduation
Like their peers in medical school, MD/PhD graduates often pursue a residency. A study of graduates of the MD/PhD program at the University of Pennsylvania from 1992 to 1998 reported that 99% of the graduates entered residency training. The most common choices among these graduates reflected the national trends, with the bulk of students entering internal medicine, pediatrics, pathology, and surgery. However, the fields of neurology and neurological surgery, ophthalmology, and otolaryngology were disproportionately favored by Penn graduates, while emergency medicine, family practice, and orthopedic surgery were underrepresented.
The imbalance of MD/PhD participation in several fields represented by this study and national statistics may result from several differences. First, certain fields may tend to be more compatible with medical research, especially fields on the cutting edge of technology. These fields would more closely correlated with the interests of MD/PhD graduates. Secondly, some residency programs may favor dual degree candidates for their maturity and interest in investigation. Many residency programs, including those at academic centers, contain a research component, and MD/PhD graduates may find their research experience more competitive for earning such positions. It is important to note, however, that MD/PhD students may naturally be more competitive and may have secured the top residencies even had they pursued an MD degree alone.
The utility of MD/PhD programs can also be measured by the retention rate of graduates in research. Upon graduation from medical and graduate school, MD/PhDs often practice in an academic setting. A recent review from NIH found that 85% of dual degree program graduates from 1975 to 1990 continued to balance research and clinical practice. NIH postdoctoral fellowships, on the other hand, have had a much poorer track record, with most programs showing only a 15-20% scientific retention rate for MD graduates.
This discrepancy can be explained by the inherent differences between the MD/PhD and MD/fellowship tracks. The investment of mentors in the success of graduate students may be less than that for postdoctoral fellows, which may discourage the MD/fellowship student's from continuing on in research. Others have felt that a two-year postdoctoral fellowship is not sufficient scientific training for the high level of competition for research funding. However, authors of studies assessing MD/PhD programs often attribute the discrepancy to the higher baseline motivation of MD/PhD students. Once again, a self-selective process would occurs in which MD/PhD graduates would naturally be capable of balancing time between a lab and clinical care and succeeding in both.
Professional Life
With complete training in science and medicine, MD/PhDs have the intellectual flexibility to alter the balance in their professional lives as they see fit. Physician-scientists take on widely varying schedules, some practicing four weeks out of the year and others visiting the clinic two days out of the week. At Beth Israel's neurology department, David Simon reports that "at a minimum, most MDs in the department are expected to have a single half-day clinic each week," and that individual schedules are arranged with the department.
A commonly cited professional advantage in holding dual degrees concerns the current emphasis on translational research. Physician-researchers "have access to clinical specimens and patients, which can be helpful for some types of research, and sometimes have better insight into the most clinically relevant questions," explains Simon. The additional research capabilities that MD/PhDs have at their disposal may increase their competitiveness for research grants that they may not otherwise be able to acquire.
However, this profound ability to merge clinical practice and research may bring a conflict of interest when the clinician may begin regarding patients as research subjects, which may alter the physician-patient relationship. Although perspectives may vary widely from physician to physician, David Simon approaches the situation gingerly. "I am careful to avoid the appearance of a conflict," says Simon. "First of all, I usually don't ask patients about research on their first visit with me but tend to wait until we become more familiar. Second, I always discuss clinical issues regarding the patient's care before raising the question of research. Third, I do mostly Parkinson's disease (PD) clinical trials, and most of my PD patients are very interested in research and quite eager to participate in research. They are experiencing first hand what a scary disease it is, and often want to do whatever they can to help."
Many physician-researchers feel subject to the bias held by full-time clinicians that they are unfocused and sub-par clinicians. The truth, however, once again varies heavily depending on the individual. Simon comments, "Many clinician-researchers are extremely talented clinicians who provide outstanding clinical care. There are some who do not, and often that group ends up drifting towards the lab and eventually stopping their clinical work." Although physician-researchers could certainly provide more extensive care if they were to see patients full-time, Simon feels that the quality bias is certainly not universally true. "I've received good feedback and support regarding my clinical care from my colleagues. I continue to get patients referred to me, even from other full-time clinicians."
A Tough Balance
Clinical practice in an academic setting may not, of course, satisfy all scientists, as attempting to excel in two facets of a professional life may be demanding. Richard Riese, now managing Phase 3 clinical trials at Pfizer, left the academic setting 11 years after graduating. Explaining his decision to enter industry, Riese notes, "obtaining grants and funding in academic medicine is very competitive and the pressure to succeed is, at times, overwhelming. I did not look forward to the prospect of having to write grants every 5 years to ensure my employment." Moreover, the "salary level in academic medicine is significantly less than either clinical medical practice or industry, making 'moonlighting' a necessity. In order to make this life style work for most physicians you either need to have a spouse provide a second income, have other sources of support, or moonlight as I did. The moonlighting eats into family time and time off so pretty soon there was very little of either."
David Simon agrees with these sacrifices, but he finds his current balance satisfying. "I do feel that I am being pulled in too many directions, but I've managed to succeed for quite some time now," says Simon. "It would not be so hard if I truly stuck to bench work and clinical care, but I also do clinical research, and combining those 3 areas keeps me exceptionally busy. But I am strongly committed to each aspect of what I do and would not want to give up any of it, so I'm willing to work hard to keep it up."
Filling a Niche
In the mid-1960s, the National Institutes of Health, academic institutions, and private enterprises realized that the thriving biomedical sciences field could create opportunities for translational research in human disease. Their efforts culminated in the creation of MD/PhD programs to train physician-scientists who would bring research insights into their clinical practice and vice versa. As rapid technological developments catalyze the explosion of scientific information, the potential for translational research continues to grow. Physician-scientists, including MD/PhD graduates, are trained to bridge the gap between the clinic and the lab.
While the sacrifices during and after an MD/PhD education may be discouraging, the intellectual and vocational advantages posed to many graduates override the costs. Those who stay in the academic setting often find their professions intensely rewarding. David Simon remarks, "My job is rewarding largely in two ways. As a clinician, I have the opportunity to treat and heal on a very personal and short-term basis. As a researcher, I contribute to the medical body of knowledge and help pave the way for innovative treatments." Combining medical and scientific expertise honed through years of rigorous training, physician-scientists embody the goals of medicine in every sense of the profession. 
Allen Cheng is a writer for the Next Generation and a student of Harvard College, Class of 2009.