For the last several months, I've spent trying to relearn what it means and takes to be a medical student after a brief research hiatus. Bluntly put, it's an entirely different atmosphere and attitude than that of the graduate school years.
First, the appreciation of time is entirely different. In medical school, we are told the hour that we are to graduate, during our orientation four years prior. In graduate school, we are told to figure out where we'll be in ten years. Clinicians are always seemingly in a rush and hurry to do something, while researchers gain comfort from methodically picking apart a problem, frequently to excess.
Comparing the stresses of graduate to medical school is like comparing apples to oranges. Weeks, months, even years can be spent in graduate school stressing over single experiments, and future opportunities and jobs can be made or broken by the success of such experiments. Life becomes endless pipettes, beakers, dishes, and time course experiments that you hope to be able to one day make a story/dissertation from. In medical school, stress is caused by the immediate situation of a human life at stake in front of you, which (with all due respect to animals) is more stressful than working with cells, nematodes, or even mice. The stresses are simply different in their own ways.
Appearances matter, in med school at least. No one cares much at all what you look like (so long as you're EH&S and IACUC compliant), and that is perfectly okay. In med school, we frequently have to 'fake it till we make it' and one of the ways of faking it is to appear the part of a doctor. More than just a physical barrier from the cesspool of pathogens that we're exposed to in clinic, the white coat serves as a metaphorical shield to hide behind when our own clinical skills become questioned.
The public reception of both realms is frequently also misunderstood. In graduate school, the most common question to receive is "When will you be done?" while in medical school, it is "What are you going into?" In this odd dual degree situation that I've finagled myself into, it most frequently is "What the heck were you thinking?"
I'm a current MD-PhD candidate, working hard to help treat and manage muscular dystrophies