“Why MD/PhD?” is probably the most frequently asked question that I somehow haven’t appropriately addressed yet on my blog. I have multiple drafts of posts that go back years that I never felt were ready for the world. I’m changing that now.

To answer this question, I must first answer another –

Why become a physician-scientist?

The general goal of MD/PhD programs is to train physician-scientists, but that is not the only way to become a physician-scientist.

The general definition of physician-scientists is that they are medical doctors who are also trained to do research and typically spend the majority of their time doing so. These medical doctors could have a MD or DO degree, or a MBBS degree if they trained internationally. They do not necessarily have to do residency training and become a licensed practicing physician. They also may or may not have a PhD. They can also get sufficient training during residency/fellowship or another post-doctoral research experience that would prepare them to become an independent researcher. And as team-based research is coming in to prominence, they may also not necessarily spend the majority of their time during research or it may be difficult to distinguish their clinical and research time if they’re involved in clinical research.

Whichever way you approach this career path, it’s a long road. So why do people do it? One reason is that the physician-scientist is uniquely positioned to effectively answer questions that arise in the clinic. For example, say you’re an astute physician who noticed a family with high levels of cholesterol in their blood and are more likely to have heart attacks at a young age. You ask whether the cholesterol is high because 1) more of it is being produced or 2) because it’s not being taken up by cells. You decide to take a sample of their cells and grow them outside a body. By treating these cells and a non-affected person’s cells with a labeled cholesterol-containing lipoprotein, you find that the affected cells do not take up cholesterol like the non-affected cells. Therefore, the cholesterol cannot provide feedback to the cell to tell it to stop making even more cholesterol! 😱 There must be something on the cell surface that is responsible for taking up cholesterol that is missing from the affected patient. Turns out, this something was the low-density lipoprotein (LDL) receptor (LDLR).

The physician-scientists in this case were Joe Goldstein and Michael Brown, who ultimately won the Nobel Prize for their work on cholesterol. Their findings were the first to show a biological process called receptor-mediated endocytosis, but they were also instrumental in showing how statins work to reduce cholesterol levels in the blood. Statins are now taken by more than 30 million people worldwide to reduce their risk of heart attacks. Neither of these physician-scientists have a PhD, but both did fellowship training in biochemical genetics at the National Institutes of Health where they had some clinical responsibility while also training in basic science.

It is important to note that not all physician-scientists are biologists like Brown and Goldstein. While this is a more traditional area of focus for physician-scientists, a physician-scientist can specialize in virtually any area of research. For example, my MD/PhD program has trained a remarkably diverse set of physician-scientists with research areas from engineering to neuroscience and biochemistry to anthropology and music. They can also be found in all medical specialties from surgery to internal medicine to psychiatry. The important thing is that whatever research area they pursue, ideally the physician-scientist would focus their research on a question related to human health.

There is a need for more diversity and inclusion in the physician-scientist workforce. Here is a paper that I co-wrote calling for a more broad discussion of diversity in the workforce that goes beyond gender and ethnicity: Diversity and the Next Generation Physician-Scientist.

But really, why MD/PhD?

Since I’ve just told you that physician-scientists do not need both a MD and PhD, let’s get back to the question at hand – “Why MD/PhD?” To fully answer this question, there’s a couple other FAQs to answer:

1. If you want to do research, why do the MD? You can most certainly do research without the MD. You can even do research that is quite clinically oriented and you can collaborate with MDs to get patient samples. So why the MD? From how I see it, the MD lets you take your research one step further and get direct input from the clinic. Maybe you’re trained as a pathologist and built a skillset reading histology during your clinical training so that you don’t have to collaborate with a pathologist for your research. Or maybe you’re practicing as a pathologist and you find something novel in the patient slides you’re looking at that you can investigate further in your lab. Maybe you shift your research focus from how to kill cancer cells to studying how cancer/cancer treatment causes nausea or other side effects because your patients frequently cite that as a major influence on their daily quality of life. Or, at a more fundamental level, you simply want to care for patients as part of your career because it brings fulfillment and meaning to your life. 🙌 These are just some examples how training as a physician can complement a research career.
2. If you don’t need a PhD to be a physician-scientist, why do the PhD? A majority of physician-scientists do not have a PhD. Unfortunately, this is subset of physician-scientists that is facing the largest decline. Training in a PhD program provides rigorous and structured research training that is not included in the basic medicine curriculum. Typically, this is the only time of one’s career development that is solely dedicated to research. In any other case, there will be clinical and/or teaching duties that distract from the research at hand. Many fellowship and some residency programs encourage research, and by having a PhD in advance, you are more likely to hit the ground running. There is a large learning curve that often gets overlooked regarding topics such as experimental design, statistics, etc. – aka the responsible conduct of research – that are barely discussed in med school. Doing a PhD gives you time to develop your critical thinking skills and understanding of these areas.

So why did I decide to do MD/PhD? 

I had always thought I had to choose between a career in research and a career in medicine – I initially chose the former. I felt that the ultimate contribution I would like to make in the world was the creation of new knowledge, preferably knowledge that would have a somewhat direct link to improving human health. Then I found out about MD/PhD programs and the opportunity to combine research and medical careers, which was exactly what I was looking for, largely for the reasons described above.

While my research and clinical interests have evolved, my ultimate approach to my career remains quite similar. I wrote in my MD/PhD personal statement that I wanted to study cancer. My course led me to liver cancer then to liver disease and metabolism more broadly. Writing this as I begin my 8th year as a MD/PhD student and 3rd year of medical school, I know that I want to both practice medicine and do research, but I still do not know exactly how I want my career to look. Will I do more basic research like my PhD? Will I do more clinical research? Will I be more involved in advocacy and healthcare leadership? Only time will tell. Nonetheless, I am confident that the MD/PhD path was right for me and will prepare me for whichever direction my career takes me.

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Featured photo: Physician-scientist and Nobel Laureate Eric Kandel (center) with some cool physician-scientist trainees (📷: American Physician Scientists Association)