Do children eventually "outgrow" ADHD?
No. ADHD is a neurobiological based disorder. We know that at least 60 % of all children with severe ADHD will continue to show severe symptoms as adults. But symptoms might change: hyperactive movements or impulsive behaviours might be reduced. So some children no longer meet the diagnostic criteria for the hyperactive-impulsive type. But normally they will still have attentional problems and even more problems due to deficits of their executive functions and self-organisation.
So they might "outgrow" diagnostic criteria, but will still have the neurobiological vulnerability of ADHD.
This can cause different kinds of problems in later life due to maladaptation at work, partnership or secondary problems of substance abuse or impulsive behaviours.
Many ADHD-adolescents are especially prone to substance abuse problems or problems with discipline at school or work due to their deficits in impulse control and self-organisation. However, many adolescents or adults develop positive traits and can use positive aspects of this "disorder". They learn to adapt in every day life and will no longer feel handicapped by ADHD-symptoms. But the biological vulnerability is still present.