Definition - What does Controlled Substance mean?
Controlled substances are drugs whose sale and use is regulated by federal and state governments. In some cases, doctors can prescribe controlled substances. However, those who are not doctors, or who have not been legally prescribed a controlled substance can face criminal charges if caught in possession of such a substance.
Justipedia explains Controlled Substance
Controlled substances are highly regulated because they are considered dangerous. Certain drugs can have a high addiction rate or they can be easy to overdose on. This contributes to their classification as a controlled substance. A person who is caught with a large amount of a controlled substance can face a more serious sentence than someone who is found with a very small amount of a controlled substance. This is because a person with a large amount of a controlled substance could be perceived as someone with an intent to distribute or sell the controlled substance.