From what I know about benzodiazapines ( anti-anxiety's) is that all of them are addictive and withdrawal from any one of them can be horrible.
you are right, xanax is highly addictive and should not be taken every day. For a severe anxiety attack, yes it is good. If you are put on xanax, make sure you are put on the losest dose possible: you can always go up. Xanax has been known to knock a 2oo lb. man off his feet.!!!!!
Ativan is another fast acting benzo, but is less potent than xanax.
Klonopin is another benzo...anti-anxiety as all are, but the half life of the medication lasts longer than the others. For instance you can take two klonopin a day and it helps..whereas after 4-6 hours the effects of xanax or ativan wear off and you need to take more.
I am on lexapro also.....it has an anti anxiety component to it also and it doesn't help u gain weight. It can even help you sleep.
Hope that helps,
best of luck and many hugs,
Krissie