Adderall was originally formulated and marketed as a diet drug. It had already been approved before it was rebranded and remarketed for ADHD, and the criteria f

Adderall was originally formulated and marketed as a diet drug. It had already been approved before it was rebranded and remarketed for ADHD, and the criteria for approving a new on-label use is significant but not as rigorous as approving a new drug. Drugs that are still under a patent have a company with the incentive to go through the expensive approval process while generic drugs lack that. So a wacky mix of amphetamines designed as a diet drug that are still under patent have more corporate backing for that approval process than plain old generic dextroamphetamine, which has been around forever. There’s a similar story with the use of esketamine versus ketamine to treat depression.