I had to write a paper at Law School about the treatment of suicide in legal history. IIRC, it was always taboo in the Western European societies I looked at. Problem is, criminal law can't punish people who are no longer with us. Some places tried to take away the inheritance rights of the person's beneficiaries as a deterrent. I think life insurance policies are void if there is a suicide.
It is a crime in Canada to assist another to commit suicide.
http://www.answers.com/topic/suicide