Trying Coffee For ADHD

I have heard it mentioned several times that coffee although a stimulant for some people actually has a paroxysmal effect on people with ADD/ADHD.
Kinda like giving them stimulant drugs like Ritalin and such.
It has a reverse effect on them and actually serves to calm them down for a period of time.
I looked after a man in Bismarck, I think it was, who said that he spent some time in a rehab unit in Chicago and from the window in his room he could see a school.
In the mornings he noticed that all the children getting off a particular bus were all carrying thermos flasks and he commented on it to one of the nurses looking after him.
She told him that they were children with ADD/ADHD and they were running a trial. The children were carrying coffee in their flasks and at certain times during the day, the teacher would instruct them to drink some.
Well at that time I thought it was worth a crack so offered some up to John to see what would happen.
I served it black with no sweetener as I thought that would detract from the effects of the coffee.
Naturally enough, he wouldn't take it.
Haven't thought much else about it but one of my friends brought it up to me last night. She says that she gives it to her son and it works pretty well.
We discussed it a bit and I discovered that she not only uses creamer but a small amount of sweetener.
So, this morning, I brewed some up for John.
He drank it without a problem which was nice. Then off he went to school.
Nothing was written in his folder about his mood or behaviour today so I asked the lady who dropped him off and mentioned the coffee.
She said that he was fairly calm in the morning but was a little wound in the afternoon.
I suggested sending a little with him so they could give it to him with his lunch to see if it made a difference in his ability to concentrate.
A short while ago he was starting to get a little flappy and he was bouncing around the bedroom so I gave him a small amount.
It has been half an hour and he is still somewhat loud but he has ceased jumping on the beds so we will see.
Later on I will research and see if I can find some more info on it as to amounts and times etc.
If anyone else has tried it on their children and wants to leave a comment, that would be real helpful.
Later.