Google aspartame. Find the research that makes some people avoid aspartame like the plague. Then decide if you still want it in your body. I use stevia and raw, unprocessed honey, or in a pinch, sugar. Since fructose and any ingredient ending in -ose are also detrimental, we all need to think fruc fructose, or any ingredient ending in -ose! Another natural product has been found in---perhaps South America? Don't recall the details, but when I see reference to it again, I'll check it further; sounds like it would be okay. When you know something is harmful to your body, but you dearly love its taste, you've got to use self-discipline. Use the baddies only on special occasions, which might amount to 10-15 times a year. But I NEVER knowingly consume aspartame, or that product that the manufacturer wants you to think is "splendid." While you're googling, check out the diseases that have brain lesions, or visit any nursing home where you'll find real live humanoids who have those diseases. Then start advocating for pure water, which tastes so much better than chemical laden tap water. We all develop a taste for everything that we like. Babies make a face every time they're introduced to a new taste. We need to educate our tongues. When you're a little kid, all candy tastes good, and you don't understand why, the older people are, the more they like those tiny pieces of candy, when a candy bar is so big by comparison. But as you get older, you savor the wonderful, incredible nuances of fine chocolate candies, and given the choice, you reach for those tiny candies. We devlop a taste for pure water and pure foods. We can---we have the ability to---choose well. Our decisions ultimately decide how old we will be when we become nursing home residents---or not.
You could ask your psychiatrist about what there is besides Neurontin for anxiety. As for aspartame that can worsen depression. Its known not to be good for people with clinical depression. I'd avoid it. But regular soda with sugar will cause you to gain weight. Its a headache but perhaps do as I do and have flavored seltzer water. My medication makes me want to eat foods with sugar as well as soda and I have to avoid weight gain but aspartame is not good for me either.