I have taken several other drugs before this one (Prozac, Welbutrin, etc...) and currently on the highest dosage of Citalopram available.

Perhaps you would benefit from escitalopram. It goes by the brand name of Lexapro. No generic is available yet. Escitalopram is a derivative of citalopram and is more potent. As a rule of thumb, 20mg of escitalopram = 40mg of citalopram. But that's just a rule of thumb my psychiatrist came up with from his experience.

I've experienced far fewer side effects (lethargy, brain fog, decreased libido) from Lexapro than I did with Celexa (citalopram). I'm on different meds now though I still take some Lexapro. It's powerful stuff.