Highly

http://focus.psychiatryonline.org/article.aspx?Volume=2&page=558&journalID=21

soheil1for moderately disruptive boys, compared with highly and nondisruptive boys.

This phrase is poorly written.

It's speaking of three categories of boys:
1. boys which are highly disruptive
2. boys which are moderately disruptive
3. boys which are not disruptive at all, or "nondisruptive."

The author is tr

But it said it only influences botes with moderate disruptivity, and you say it influences all groups, albeit to different degrees..........

That's true, but "only" is an absolute, and "compared to" is relative. It's a mismatch. You can't use them together.
The guy needs to study English.

I can't say, "I never make mistakes compared to you."

He didn't say 'compared to'.He said 'compared with'.
Maybe he meant 'rather than' by compared with'?!

And, may I safely replace "highly" with "very"?

soheil1He didn't say 'compared to'.He said 'compared with'.

I don't find any significant difference in meaning between the two.

soheil1Maybe he meant 'rather than' by compared with'?!

Maybe he did. His sentences leave us to wonder what he meant. We can only speculate.

soheil1And, may I safely replace "highly" with "very"?

Yes, you may. But doing so will not rescue your author's sentence. It leaves the same problem.