Health Secretary Robert F. Kennedy Jr. has often criticized prescription stimulants, such as Adderall, that are primarily used to treat attention deficit hyperactivity disorder.

“We have damaged this entire generation,” he said last year during a podcast, referring to the number of children taking psychiatric medications. “We have poisoned them.”

In February, the “Make America Healthy Again” commission, led by Mr. Kennedy, announced plans to evaluate the “threat” posed by drugs like prescription stimulants.

But are they a threat? And if so, to whom?

Like many medications, prescription stimulants have potential side effects, and there are people who misuse them. Yet these drugs are also considered some of the most effective and well-researched treatments that psychiatry has to offer, said Dr. Jeffrey H. Newcorn, the director of the Division of A.D.H.D. and Learning Disorders at the Icahn School of Medicine at Mount Sinai in New York.

Here are some answers to common questions and concerns about stimulants.

What are prescription stimulants?

Prescription stimulants are drugs that help change the way the brain works by increasing the communication among neurons.

They are divided into two classes: methylphenidates (like Ritalin, Focalin and Concerta) and amphetamines (like Vyvanse and Adderall).