Generally no. I mean, psychogenic stuttering exists but it's rare and mostly happens to adults. If you started stuttering as a kid like the vast majority of us, it's just developmental stuttering which isn't caused by any of the things you mentioned. Most people dont' stutter when they're alone, on molly, or singing (singing uses a different neuropath than speaking and you're also creating constant phonation). Being drunk helps some stutterers, makes others worse. In short, none of those things cause stuttering, they only make it more difficult.