Xanax(Alpazolam) is used pretty specifically for anxiety disorders and panic attacks. It also has a pretty hefty list of negative side effects (suicide, hallucinations, jaundice, skin rashes etc). It also carries a pretty strong likelihood of physical dependency. Valium(diazepam) uses vary a lot more than Xanax, which has primarily one use, Valium can be used to treat things like restless leg syndrome, insomnia, withdrawl from alcohol etc. It is also occasionally used on cats and dogs as a short term sedative. Klonopins(clonazepam) can (like valium) be used to treat a variety of different things. Though it does focus mainly on anti-anxiety and depression. It's list of negative side effects includes such long term effects as- depression(ironic, no?) and sexual dysfunction. It also can create a heavy physical dependency. This drugs can have incredibly positive effects on your life when used safely and under the care of a doctor. However, when taken without medical supervision(trust me) they can really mess up your life. Hope I've helped!