What Are the Illegal and Prescription Drug Categories?

Ron Kilgarlin

February 27, 2023

There are thousands of drugs in the world, all with different chemical properties and effects on the mind and body. To help organize them, scientists tend to group them into broad classifications based on their chemical similarities.

In the United States, there are five drug schedules under federal law that restrict the use of certain substances based on their accepted medical value and potential for abuse and addiction. These schedules apply to narcotics, psychotropic substances, and synthetic drugs.


Stimulants are drugs that temporarily increase the functional activity of your body’s nervous system, causing a number of effects, including higher mental alertness, increased physical activity, and appetite suppression. There are many legal and illegal stimulants, including caffeine, nicotine, and the prescription medications Adderall and Ritalin.

These medications are used to treat ADHD (attention-deficit hyperactivity disorder) and narcolepsy. Illegal stimulants include methamphetamine, crystal meth, cocaine, and ecstasy (MDMA).

Misuse of stimulants can lead to serious health problems and death, particularly for young adults. Repeated use can result in psychological and physical dependence, and overdose can cause fatal complications.


Depressants are a group of drugs that work by slowing the activity of the central nervous system. They are also known as “downers.”

These drugs are useful for treating conditions such as anxiety and sleep disorders. However, they have the potential to become dangerous if misused or abused.

The main risk of depressants is overdose, which can be deadly if taken in excess or at elevated doses. This can slow breathing and heart rate to fatally low levels, causing seizures or death.

Benzodiazepines are the most common type of depressant drug used to treat anxiety and sleep disorders. They are available in prescription and over-the-counter forms.


Hallucinogens alter a person’s perception of reality, causing hallucinations and other unusual sensations. They can be abused and sometimes lead to addiction.

The legal status of psychedelic drugs varies from state to state and from country to country. It also depends on how the substance was grown or manufactured.

Hallucinogens include psilocybin (magic mushrooms), DMT, LSD, PCP, and Ketamine. They all cause hallucinations and other unusual sensory experiences.


Opioids are a family of drugs, including prescription pain relievers like oxycodone (OxyContin(r)), hydrocodone (Vicodin(r)), codeine, morphine, and synthetic opioids such as fentanyl. They reduce pain but also can cause drowsiness, confusion, and euphoria.

Prescription opioids are often used to help people with serious health conditions, like cancer, recover from surgery and manage chronic pain. However, misuse and addiction can occur with these medications.

Taking opioids in higher amounts or more frequently than prescribed increases your risk of an overdose, which can be fatal. The risk increases even more when you take them using methods other than the ones your doctor recommends, such as crushing a pill and snorting or injecting it.


Inhalants are a group of breathable chemical vapors or gases that produce mind-altering effects when inhaled. These include solvents (liquids that vaporize at room temperature), aerosols (spraying liquids containing propellants), and gases, such as nitrous oxide or amyl nitrite.

The use of inhalants, particularly by children and adolescents, is becoming a serious problem throughout the United States. About 1.9 million people aged 12 and older used an inhalant in the past year, according to the National Household Survey on Drug Abuse.

Inhalants are a group of chemicals that produce psychoactive (mind-altering) effects when inhaled. These substances are commonly found in household products such as spray paints, glues, and cleaning fluids.