The long term health impacts of taking prescription stimulants at recommended doses for on-label management of disorders is well understood and extensively studied/documented. There's not a psychiatrist that's not going to take this and other factors into consideration when prescribing it and any decent one is going to discuss medication breaks with their patients they prescribe them to. Prescription stimulants aren't perfect but it's currently the most effective treatment that's broadly applicable and well-tolerated.
A lot of people are critical of prescription stimulants without presenting a comparable alternative that will allow disordered people (particularly adults) to maintain the ability to function, be productive and maintain happiness in our current society with it's expectations and capability requirements.