Don't use Prozac. If you are truly concerned about your dog's emotional state, go to a certified veterinary behaviorist for help. I have a +R trainer who would easily suggest a prong for safety and maintenance, if needed, while also working on training the dog to walk with a flat buckle collar at home and then slowly out into the real world, so you can eventually wean off of using one. Make sure it is fitted properly, it's the right size and don't get a cheap one.
I have never used prongs on my dogs, but when I did rescue and would get two year old Labs that lived in backyards 24/7 -- so both untrained and easily overstimulated -- I often used a prong out of necessity and it usually worked out OK. There were some dogs that were terrified of them and some that were in such an emotional state that they literally did not feel them and a head halter worked better for the same reasons it works on a horse (control of the head). You have to properly condition the head halter and for some dogs it takes quite a bit of time -- you would take the halter off before they are upset about it otherwise you're conditioning them to hate it. You can't rush the process.