controlled substance vs drug

controlled substance and drug both are nouns.

Word	Noun	Adjective	Verb	Adverb
controlled substance	Yes	No	No	No
drug	Yes	No	Yes	No

As nouns, drug is a hypernym of controlled substance; that is, drug is a word with a broader meaning than controlled substance:

controlled substance: a drug or chemical substance whose possession and use are controlled by law
drug: a substance that is used as a medicine or narcotic

controlled substance (noun)	drug (noun)
a drug or chemical substance whose possession and use are controlled by law	a substance that is used as a medicine or narcotic

controlled substance (verb)	drug (verb)
	administer a drug to
	use recreational drugs