What is a controlled substance?

A controlled substance is a drug or chemical substance regulated by the government. These substances are typically categorized based on their potential for abuse and their accepted medical use. Controlled substances are subject to legal restrictions and regulations concerning their manufacture, possession, distribution, and use. The classification and scheduling of controlled substances may vary between countries and regions. Examples of controlled substances include narcotics, stimulants, depressants, hallucinogens, and certain prescription medications.