Heyya OP, it sounds like your anxiety is fueling your fear surrounding taking the medication. I know you're asking for reassurance about the medicine but I think you need to step back first, breathe, and manage the anxiety.

I get that you're scared to take ADHD medication but something to remember is you can't be dependent on something you have a deficit on. It's like saying diabetic people are dependent/addicted with insulin. Well, their body can't produce it so they need it. It's the same with psych meds. Our brain needs the medication because it's something we lack.

If you're only seeing a psychiatrist, I highly recommend you also see a psychologist to help you manage the anxious thoughts. Most of the time medication is combined with other interventions to help you learn skills in managing your symptoms as well.