How do clinicians decide which ADHD medication to start with?

This is a great question! ADHD meds are often interchangeable and it ultimately comes down to symptom profile and any underlining patient conditions. for example, vyvanse is a prodrug and relies on your gut motility for absorption so if you have IBS-D, its unlikely that it would be a good drug for you. Alternatively, it can also just be pure experience. For example, I have see good response with concerta and so I will start with that and if we arent getting the effect we want, the we can switch. But research wise, they are all effective and it comes down to individual and provider differences