M2 vs. M3: You’re Taking USMLE Step 1 When?

If you’ve learned anything up to this point in medicine, it’s likely that the field has strong foundations in dogma and tradition. Routinely, medical school consisted of two years of basic science classroom work followed by two years of clinical clerkships, with these two phases being separated by our timeless friend (or greatest nemesis), the USMLE Step 1 exam.

In recent years, however — and amid the COVID era — many schools have positioned Step 1 at the end of third year, just after completion of clerkships. The impact this has almost certainly depends on each individual student. What we can tell you, however, is how to use your third-year clerkship experience to your advantage if you happen to be in one of these programs.

First, the good:

There are obvious advantages to taking Step 1 at the end of third year. After an extra year of intense medical education, you are a smarter person, and you are closer to being a doctor. More importantly, at this point, you should have developed the habit of thinking like a doctor. It is something that we at MST come back to all the time: forming a broad yet pointed differential diagnosis in your head, and using further information to winnow it down to a definitive diagnosis.

Why is diagnosis such an important part of the exam? As you progress through Step 1 vignettes, you will find that nearly every answer asks you for:

  • the diagnosis itself
  • the expected history, physical, or lab findings (which require knowledge of the diagnosis)
  • the treatment (for this particular diagnosis)
  • the pathophysiology (of this particular disease)
  • the pharmacology of the drug in question (which treats this disease)

It is very difficult, and often impossible, to answer a Step 1 vignette-based question without first establishing a diagnosis.

By seeing those hundreds of patients as an MS3, whether you know it or not, you have gotten in the habit of forming differentials. In the ED, when you know you are going to see a 60-year old man with worsening cough, you are probably already thinking pneumonia vs. COPD exacerbation vs. viral respiratory infection. It might even be an AIDS patient with PCP, or sarcoid or TB. But as an MS3, you are no longer trying to wrap your head around the difference between typical and atypical pneumonia. You have probably treated a patient with one of these diseases, and in doing so, learned about it, as well as its counterpart, inside and out.

There is a greater benefit to you as a learner to see and know a patient with a disease, rather than recounting facts off of a page in a book. Mr. Sullivan who had a heart attack was a man with a beard and an occupation and a family and chest pain. He was not a collection of symptoms and drugs on page 187.

Furthermore, an individual patient gives us an opportunity to learn about multiple facets of a condition.

After Mr. Sullivan’s MI, we know he is taking his aspirin as an antiplatelet agent, but had to switch from an ACEi to an ARB because he developed a dry cough. Come to think of it, he takes clopidogrel, atorvastatin and metoprolol, too. Just from that, we have internalized post-MI management, and learned about five drugs along with their side effects. We learn from our patients!

If postponing Step 1 to the end of third year was proven to be overwhelmingly better at making us better doctors and improving patient outcomes, then every program would be doing it — there must be a drawback.

By inserting an extra year of clinical experience before Step 1, you are putting your classroom basic science learning further and further into your rear-view. Do you remember your essential amino acids? The genetic inheritance pattern of neurofibromatosis? Or what Fabry’s disease even is? Out of the students I’ve talked to who are in these types of programs, few had concerns about having to “relearn” all that biochem, genetics, immunology, and other topics that had become more distant. 

“You have to cram them to some degree anyway,” one student told me.

And the more I thought about this, I realized it was entirely true. It is hopeless to think that after 18 months, all those mucopolysaccharidoses and individual cytokines are fresh. They beg to be restudied multiple times during your dedicated Step 1 study period anyway. Whether they were learned 18 or 30 months ago isn’t very consequential. Like so much knowledge in medical school, the natural pattern is to learn, memorize, temporarily forget, and then kick this knowledge dust back up to the surface when needed. And each time we do need to relearn material, it gets a little easier to recall.

I’ve written before (Take it to the Max: Top 4 Ways to Get the Most Out of Medical School) that the progression of medical school can feel awry at times. Like when you have to master maple syrup urine disease, yet you haven’t learned about aspirin yet. Or when you are memorizing your 12th muscle of the forearm but can’t tell your friend/mom/cousin why their back hurts. This crazy schema is put in place for a reason, and has been used to train millions to become doctors. While it might not make sense now, medical school will teach you how to diagnose conditions and how to think like a doctor. By the time you finish, it should make a lot more sense. 

Your take-home lesson is this:

As an MS3, get in the habit of deliberately coming up with a good differential diagnosis both in real life, and when studying for Step 1. Don’t get hung up on the distance that has pushed your basic sciences so far from you. You were going to forget and relearn it anyway. And no matter when you take Step 1, the only thing that can ensure success is hard work all the way through.

When does your program suggest you take Step 1? How do you and your classmates feel about this?