Is there one?

Specifically, right now one of my characters is marked as "Cursed", but i see no decreased stats or anything else that could give me a hint of just what exactly happened to him, and there is no tooltip saying what the effect does.

^What she said, but, for the record, you can also find info regarding the various special conditions in the manual (albeit in not as much detail); it's on page 36.

Huh. Highly interesting, that. And way too well hidden. >_>

Another thing not mentioned there, but I could have sworn that cursed person, when not treated in time, dies.

That's what I remember from playing anyway. maybe it's time to reinstall and test that theory ;)

I was playing MM6 and all my characters were cursed, it seemed I took some pretty major damage to both HP and SP. All the characters should have been full but all but one were nearing unconsciousness. Went to a temple very quickly after that, the only one in my area was a temple of baa though. Any penalty for using them?

Bad reputation.
Cheap healing though ;)

totally worth it sometimes