Can BuSpar have an immediate effect?

Hi, Flurppity!
Buspirone in general takes at least one to two weeks to have an initial effect and generally can take up to four to six weeks to actually have its full clinical effect.
It would be unusual for it to work immediately although I've heard that some doctors have prescribed it to be taken as needed.
It may be that you're experiencing a placebo effect but who cares. If it works for you fine but I would still take it as prescribed and give it a "fair trial" of a few weeks.
Personally, I've taken buspirone (BuSpar) for many years and it is more effective than any other medication I've tried.
Best regards and I hope it works as well for you.