This Sunday is World Laughter Day, a 16-year-old holiday puffed into existence by the guy who created something called “laughter yoga.” That means that all weekend long we’re going to be bombarded with articles about the benefits of laughter. Didn’t you know? Laughter is good for your arteries, it boosts the success rate of IVF, and even treats cancer!

I have nothing against laughing, I even do it occasionally. But when it comes to the science of laughter, some of the most interesting studies are those describing medical cases in which laughter foretold sickness.

I’ll describe three of them here, all published last year:

Take the case of a 52-year-old woman who had been