Trying a second stimulant after the first one didn't work: does that mean the diagnosis was wrong?

No, not trying a second stimulant doesn't call the diagnosis into question, it's actually a standard, expected part of ADHD treatment. Roughly a third of people who don't respond well to one stimulant class do respond well to the other, amphetamine or methylphenidate, and there's no reliable way to predict this in advance. Medication response and diagnostic accuracy are assessed through entirely separate processes: diagnosis relies on structured clinical evaluation against DSM-5-TR criteria, while medication selection is a trial-and-response process guided by CADDRA's algorithm. FasTreat also offers private online ADHD assessment and ongoing care, depending on your needs and clinical assessment. Related reading: https://www.fastreat.com/en/adhd-faq https://www.fastreat.com/en/blogs/adhd-medication References: https://www.caddra.ca/wp-content/uploads/Canadian-ADHD-Practice-Guidelines-4.1-January-6-2021.pdf