Like the other posts said, xanax can be addictive. The long-term effects would be that you would need more and more the longer you take it as your body becomes immune to the dose you're currently taking. People who suffer from anxiety need to speak with their doctors on what meds, if any they should take, or if speaking with a therapist would be more helpful. Best to you!
I have been taking Xanax 1mg 3 times daily since its release in the US in 1985. The only long term effect of it for me ( after 25 years of daily use ) is it has such a short half life that now if I am under severe anxiety and stress, it feels like I took an asprin. It doesn't work very long after long term use. A person gets Tolerant to it and it may or may not help depending on the severity of your anxiety or stress when you take it.
Good Luck
Not exactly sure, but I have heard that you need more and more of it over time because your body gets used to it. I was on xanax for a while but my doctor switched me to Klonopin because it wasn't as addictive as xanax, he said. Not sure if I would recommend Klonopin since I still feel stressed a lot but I'm afraid to stop taking it! LOL! Good luck to you!