We're all different. Some of the sugar substitutes (besides an after taste that makes me shudder) really mess with me, so I avoid them - except splenda in pie.
(Only when our apple tree gets picked, or we hunt down the wild blueberries. Oh, well. I admit it. We freeze some blueberries for a winter pie. Shame on us. The apple tree is too young for that, yet.)
The difference with caffeine is the increased urge-pain-level, and that so drastically increases the urge without necessarily increasing the output (just more often). I get a latte just as I'm leaving for the 35-minute drive home, only. Herbal tea seems to make my body act like caffeine, without the pain or the "high".
I haven't really gotten the Doctors to tell me if any of my meds, that aren't specifically for incontinence, affect my incontinence. I haven't found an adverse interaction listed. But would the incontinence effect be listed? They don't seem to care.
I've done some experiments, and this forum has given me more to try, so look around, try your own experiments. Pretend you are avoiding sugar to prevent tooth decay. Mark Twain had a whiskey every night; but just to prevent tooth decay, you understand....