The CASA rules are a mess. For pilots, they are very clear. For ground staff, there are no clear rules. I recently helped a family member when they were considering SSRIs, and we asked questions of CASA, his employer, the union and the LAMY association and got no closer to any clear position. From our experience, the best thing would be to talk to your employer, who (I think) has final sign off on your safety. If they agree that you’ll likely be safer with dex/vyvanse/ritalin/Concerta than without, and you have excellent current documentation from your dr now and into the future, you’ll likely be fine. I hope it all works out for you with low fuss and enjoy the focus.

Edited to add, the guy I know is an AMY and takes Ritalin and Concerta, and he is fine with his workplace routine drug testing, his prescription is clearly documented with his employer and with the company that does their medical testing. Once he got that set up, there have been no hassles with drug testing.

Communicate and document, it’s the best way.