You coould write one but I don't think it would work but remember the rule of three. I only ever cursed someone once. I don't think it worked. I put a curse on someone who was mean to me to lose their popularity until they became a better person, but I took it off after a few weeks because I felt bad. They got kicked out of class anyway.
You can't change the physical body with Magickal means more drastic than moving small amounts of cells (like helping to release blocked arteries using biokinesis, which is very, very complicated).
That being said, spells created by the caster actually work for the caster better than others, often times. Another thing to note is that the rule of three is not entirely a universal law (that's not to say that someone won't try to wish negativity on you for casting ill upon them).
All in all, I'm saying to be careful. I cannot stress this enough.