One thing, though, is that Aspartame has been accused of all kinds of things by anti-sweetener zealots over the years, without any kind of experimental or even rigorous correlational evidence at all. Those kinds of symptoms — say like short term memory loss — were foreign to me so I was not much worried about it. But this depression link is different.
Research is not necessary when you can verify cause and effect for yourself. Every time I have had Aspartame in the past five years I have had a pounding headache within 2 hours. Sure a dozen or so episodes could be a coincidence, but I have enough personally collected data to convince me to avoid it.
Cheers...