I haven't been on much recently but I wanted to come back and share my experience, to help anyone in the future who might have a similar question. This might be a little long, but I wanted to include the details because it did work a little different than back home, and thought it would be good for anyone who wants to know what to expect.
For background info, I have mostly taken Adderall but switched to Concerta (Methylphenidate, same as Ritalin but time release) when I was planning my move because I knew it was not easily available in the UK. I also take Wellbutrin, which is not available at all and I will continue to have provided for me by the physician in the US. I live in Scotland.
I did bring some of my records over, but only from 3 or 4 appointments going back a year or so. It documented that I was on Adderall and then switched to Concerta. I think I would've been OK without them as long as I could provide some proof I already took Concerta (like a pill bottle with my name), but it did help and my GP was happy that I brought them.
My GP said that he could continue to write my Concerta script no problem, but would have to send me to a specialist to see about switching. The Concerta wasn't working for me, so I did have them refer me to a psychiatrist.
The psychiatrist already had my records, which my GP had scanned into the system. He said that people who don't do well on methylphenidate tend to respond better to dextroamphetamine (and vice versa) so he offered to start me on that. He said he had to start me on the lowest typical dose (5mg) and then would see me back in two weeks and talk about adjusting it.
He said his secretary would send over a letter to my GP to write the script, but also gave me a letter to bring them so they could process it faster. When I brought them the letter I didn't say it was a prescription, which apparently I should have done. This delayed me a little bit but it was fine.
My husband picked up the script from the GP for me, but because it is a controlled substance wasn't able to fill it at the chemist for me. This is the opposite as in the US, so I thought that was funny.
When I did pick up the meds they needed me to show ID and sign for it. They said that it was not a common drug, but that they had a little in stock and if I stay on it they will make sure to order more.
Today I went back to my psychiatrist, and he told me he did some research and found a document published by the NHS on switching from Adderall to a UK-available drug. It recommended dextroamphetamine, and said that the doses were equivalent. So if I was taking 10mg of Adderall, I would probably be on 10mg of dextroamphetamine.
He upped my dose to 10mg and said to just double up on the 5mg ones for now. He said he would send another letter to my GP letting them know, and for me to call next week and ask if they could just start writing me the new dose or would like me to come in for an appointment first.
He also said it was good to try and always go to the same pharmacy because it is a controlled substance and, echoing the chemist, that way they would know to keep ordering it for me.
He said I would also need to see him once every 6 months, and that I would get a letter with my appointment. But if I had any issues with my new dose or anything before then to just call and they would see me no problem.
Additionally, he asked that I get my blood pressure and weight checked at my GP once a year. He also said that once a year I am to take a "vacation" from the meds to make sure I still need them. Basically I tell people around me I'm going off the meds and then stop taking them for a week and see how I do.
So that was that! Overall pretty painless, and it only took about 2 months from start to finish. I'd be stuck waiting way longer than that in the US just for a new patient appointment with a GP, so I'm pretty pleased.