Neighbor's son was a premature baby and even if not diagnosed ADHD he was very hyper as a young child, and later got into "real" trouble. Then again my cousin was born after about the same number of weeks and she turned into a smart, caring and well functioning person. But then again the neighbor had some radioactive rain fall on her while pregnant so maybe that helped too.

You cannot have both ODD and conduct disorder (at least not according to the old DSM, don't know about now). It's either-or.