I would definitely let her try it. I was undiagnosed and did not get medication until 10th grade, and my freshman year was the worst and I fell so behind. It’s only going to get harder without.
I would seriously recommend finding a new psychologist if he thinks those are interchangeable. If you’re worried about side affects, then express that to your psychologist, one that DOESN’T prescribe vitamins. Vitamins have no correlation to the ADHD mind. The brain is lacking a brain chemical. Vitamins are something else entirely.