I couldn't find a suitable response, so I didn't vote.....
As far as curses go....to say whether or not I believe in curses would not be a suitable enough answer. I believe in everything to a certain extent.
Curses have some power over most people, depending on the entire psychological setup.
If the person is aware of the curse, (which is generally part of the preferred methodology behind laying a curse), then there are usually some mild to heavily aparent psychological or even psychologically caused physical results.
This of course depends upon the personality of the "victim" and their suggestibility as well as the charisma of the person who is cursing.
For the most part, cursing is a psychological game, but one must also take into consideration the influence of emotion and channeled personal energy directed in a harmful mannner toward another individual.
This sort of cursing is also based in psychology, but mostly in the area of raising confidence, then raising energy, then transforming it into a usable substance.
This is the reasoning many psychologists make for the explanation behind the "power of faith". This is how a spell is cast.....good or bad....blessing or curse. Faith, music, symbolism, etc, are ways of rasing energy that can be channeled into a spell.
Hmm....long explanation. In the end, what I'm saying is, curses are real, but NO, I haven't been changed into a newt.