As always aeh's comments are helpful (even when they are from a different thread):

"And, though not coming down one way or the other on this specific case, I will point out that antisocial behavior patterns have as much predictive accuracy as intelligence at age 3. (In a fifteen minute playground observation.) That is, the relational profile is as stable from age 3 to 16 as measures of intelligence are. (Not very stable, but somewhat.) Prosocial/antisocial skills become stable at about the same age as intelligence, too (around age 8-10), meaning that antisocial behavior patterns become entrenched and largely intractable to treatment around the end of third grade. (See the work of Hill Walker.)"