It seems that Aspartame has been implicated in aggravating both MPD and attention deficit disorder, among others. I experienced my first uncontrolled Twitching when I was doing a lot of Aspartame. I was also getting severe migraines and visual disorders including tunnel vision, moving shadows, and color dropouts (I would lose the green/blue range). All of these are known side effects of Aspartame, it seems. In some people, Aspartame is known to inhibit serotonin production.
Swell.
But what was scariest was the shaking fits (like I was having an epileptic seizure) and hypoglycemic problems so severe I was known to pass out. (Sugar revived me.) This last is why I stopped doing NutraSweet. I’m borderline hypoglycemic.
When I stopped NutraSweet, the uncontrolled switching stopped, too. It took a while for the migraines and visual disorders to work out, but they were gone within a few months, as was the switching. (The switching was severe enough that friends thought I was “drunk” because I was acting so strange, but alcohol was not involved!)