(A pilot friend refuses to drink diet drinks with the stuff in it, and says that many European countries forbid pilots to drink it, because the stuff has a negative effect on IQ and reaction times. )
I was on anti-seizure medication from the ages of 2 to 12, and I was told to avoid large amounts of drinks containing NutraSweet because in high doses it could trigger seizures in susceptible persons. — Joe
Anecdotal 2 cents, when NutraSweet first came out, my family swiftly discovered that it gave us all headaches at varying degrees. I haven’t had it in ten years, since once you get a reaction three or four times, you don’t keep checking to see if it still happens, but it was icky to me way back when.