You typed nuclear, but from your subject heading I'm assuming you meant Buspar. That drug is often used in conjunction with an antidepressant when the antidepressant is working but not well enough. You say you're on the highest dose of Celexa, but there isn't actually a highest dose -- some docs will always go higher, though that's not necessarily a good idea. They do it anyway, especially if you've tried a lot of stuff and nothing else has worked they will take risks. If your dose of Celexa is really high there is a hypothetical chance you could get serotonin syndrome from adding Buspar, as it does have some effect on serotonin, though not nearly as much as Celexa does. Know that if you research Buspar, it hasn't done particularly well on clinical trials when used alone, but docs do seem to believe it helps as an augmentation for a drug that isn't working well enough. But if you're tapped out on the Celexa, meaning it doesn't work for you anymore and it's not doing anything at all for you anymore, that would make any augmentation of it less likely to help. You can only augment a drug that is working. If you look up augmentation on the NIH website, you'll see that combining drugs takes effectiveness from 30% to 50%, but I wouldn't take those numbers too seriously -- the studies usually use small numbers for these drugs and only study them for a short period of time, and further, determine if a drug works or not by giving the study subjects a questionnaire, which is not a very objective way to truly determine if something works. It could also be a placebo effect, and if the study is short-term it won't pick that up. A better way, but probably too expensive and too prone to limit pharmaceutical company and psychiatrist's profits would be to follow a large number of patients for a couple years and see if their lives get materially better. But not going to happen. Something else to consider -- has anything happened that might have increased your anxiety? Remember, no mediation cures anxiety. They only tamp down symptoms. The only known cures are spontaneous remission and therapy and lifestyle changes,not meds. If you don't change the way you think, when you stop a med the problem is still there, just as it is when a med stops working. Sometimes, though, the med gives you a long enough period of relief that you do change the way you think, but you can only know that if you stop taking it, and that's a pain. Something very easy to try if you haven't tried it if you do need to change antidepressants is Lexapro, as it's almost the same drug as Celexa but different enough that while it's unlikely to give you withdrawal problems to switch between them they are sufficiently different that people do often have different side effects and results. If you switch to any other antidepressant, you'll have to go through a very slow taper off before trying something new to have the best chance of avoiding bad and long withdrawals, so Lexapro would be easy to try, though so similar it's less likely to work any better than the Celexa. All the best.