[tomstokes]

This 75% number is not from a formal study. The number supposedly comes from quotes from 3 different psychiatrists who quoted the same 75% number.

The author verified the 75% number by asking her Facebook followers.

  Do most med students require psych drugs for day-to-day
  survival? I turned my question over to Facebook: “75% of
  med students and residents are taking either stimulants
  or antidepressants or both. True or false?”

She cherry-picked a few Facebook responses to include in the article, but even some of those don't support the author's claim:

  but I have no idea if it’s 75%…I don’t know enough of my
  class well enough to have that info, nor do I think anyone
  does…there are usually cliques of up to 25 people, but for
  people to say they know for sure details of 75% of their
  class would be hard for me to believe but maybe…there is a
  lot of it, I agree with that.

And

  Being completely honest 75% seems a bit high, but I wouldn’t
  be that surprised if it were true

The author's real point is buried at the bottom: Medical licensing requires doctors to disclose their psychiatric history and medication use. Admitting previous psychiatric problems on your licensing form requires a detailed explanation of the condition and treatment. Doctors know this, so they have a perverse incentive to hide their treatment or even avoid treatment at all for fear of risking their careers.