For severe adhd which is life-threatening or threatens safety, it is. Not all children want to be hyperactive and for some it could be hell.
If it is having a serious impact to their day-to-day functioning, it is too.
As with bipolar disorder, severe adhd often requires medication (not an option) which could help wonders and give children their childhood back.
With medication there should still be counselling and good parenting, tailored to the child's needs.
However as children's brains are still developing and stimulant medications can potentially be harmful, we need to be VERY careful about it.
Stimulant medications aren't the only thing, other medications may be useful and perhaps more useful, depends on the child, their presentation may help determine which medication may be more useful
I was put on adderall at seven years old for ADHD. Now, several years down the road, if I don't take it one day, I go through withdrawal. Shaking, sweating, throwing up, having nightmares, and once, nearly passing out in exhaustion as the stimulant wore off from the previous few days.