They are subject to abuse, and amphetamines and methylphenidate are controlled substances in the United States.
The drugs commonly abused are methylphenidate, amphetamine, and methamphetamine.
Unlike methylphenidate and amphetamine, MDMA has no legitimate therapeutic use.
The most common use of methylphenidate and amphetamine in children is for control of attention-deficit/hyperactivity disorder.
The reports of growth suppression associated with amphetamines and methylphenidate are not definitive but appear to be valid.