Ativan, valium, klonopin, xanax are all in the same class of drugs called benzodiazepines. They all work on GABA receptors in the brain, the main difference with these different drugs is the half life, or the amount of time it takes for half the dose to leave your system. The shorter the half life the more addicting it can become. That is why some docs prefer one over the other for their patients, they are probably concerned with addiction possibilities. I am not trying tio sound like a know it all, but I am an RN and my husband is a physician, so I was just trying to give some insight. I am in the same boat as everyone here, I suffer from PTSD and anxiety, I do get some relief from Klonopin though. Terri