Of course, people have managed to convince themselves that aspartame causes brain cancer, lupus, multiple sclerosis, irritable bowel syndrome, headaches, and depression. So defying science for them shouldn't be much of a problem.
If it’s all the same to you I’ll stick with the scientific method.
I had a question: Why am I suddenly depressed?
I generated a hypothesis: Some change in my life caused it.
I made a prediction: If I change it back, my depression will end.
I tested the hypothesis by systematically reestablishing my old happier life one change at a time and determining its effects on my affect.
Eliminating aspartame eliminated the deep pit of depression.
Re-introducing the aspartame restored the deep depression.
Eliminating it again reproduced the relief.
Subsequent exposures to aspartame, whether I know at the time I’ve been exposed or not, are followed by bouts of depression.
Analysis shows that every repeat of an aspartame challenge results in a repeat of the depression. Subsequent removal of aspartame eases the depression. From this I can only conclude that in my case aspartame is strongly linked to depression.
I don’t know the underlying mechanism, but the data says what the data says.
You say it doesn’t.