I'm mildly autistic. Two cycles of cerebrolysin have changed my willingness and ability to interact with other people by a lot. I can now comfortably strike up a conversation with someone, where before I would just remain in the background and do almost anything to keep from interacting with anyone I didn't know really well. (Note that this is not the primary reason I'm taking cerebrolysin.)
I don't know how well that translates to ADHD, but I would not be surprised if cerebrolysin has a positive effect.