In another lifetime (or sometimes it seems that way), I was a counselor working with "emotionally disturbed" teenagers in a residential treatment facility. Every last one of them had a diagnosis of ADHD, and the program I worked for was anti-stimulant medication. I started training the youth in simple "mindfulness" exercises. We played a game called "statue", the youth would freeze like a statue and try to maintain that pose as long as they could, and I timed them. The exercise required "mindfulness of body", and I provided coaching about maintaining awareness of body movements; at first the youth could be still for 10 seconds. Then 30 seconds. Then 1 minute. When they got to 3 minutes, I would teach a basic "mindfulness of breath" exercise.
Because I was already collecting data on "on-task" behaviors in the classroom and during structured daily events, I could demonstrate a clear improvement in their ability to "remain on-task" after starting the statue game.
It's worth noting that the youth were highly motivated and they enjoyed playing the "game". In my career working with adults, many of whom are living with ADD or ADHD, the adults unequivocally dislike mindfulness exercises. I try to convince them that it is "good medicine", but few are motivated to seriously try mindfulness. I was relieved when there was a whole section in the documentary "ADHD and Loving It", where people spoke about how much they hated meditation.
"As I am, so are others;
as others are, so am I."
Having thus identified self and others,
harm no one nor have them harmed.
Sutta Nipāta 3.710