I will be studying abroad in Spain this fall, and I was wondering if anyone could give me some info about having my ADHD medication with me in Spain. I take Concerta (methylphenidate) which is a controlled substance here in the US, and presumably in Spain as well. I could probably get a 90 day prescription but I was wondering if there are any special regulations or paper work i need in order to have them with me. Obviously I will bring a written prescription and a note from my doctor.

Thanks!

That's all you'll need.

I would ask your physician if you can get the full supply in advance that you will need the entire time you are studying abroad so you don't have to try and deal with obtaining this in Spain.

I do not understand Robert how can suggest "that's all you need"
Health system is run by each autonomy area and each has it's own system.
Some systems are electronic and some systems are stuck in the middle ages and medical prescriptions are still issued by paper.
Therefore if you end up in an area which only issues medications by electronic communication to the pharmacy you could be stuck. With the electronic system stocks can be controlled to be kept to a minimum.
I am no Doctor but I done a quick search and found that Concerta is available in Spain.
However some health areas like to use generic brands.
Seeing as this is an important issue to you please do not ask on a forum if you can get it over the counter with a USA prescription.
You have to either bring enough with you and ensure you can do that or ask your education facility if they can help put you in contact with a doctor to cover you whilst you are in Spain.

I have just read your other posting questions. It seems you wish to extent your stay in Europe, maybe travel a bit.
It could be that you may have same issues of obtaining medicines in other countries.