Home > The 7 Drug Categories | Law Enforcement Guide


The 7 Drug Categories | Law Enforcement Guide

The 7 Drug Categories | Law Enforcement Guide

Drugs are undoubtedly a major concern for every police department. Whether it’s drug trafficking, drug crimes, or just perpetrators who are under the influence, police officers will undoubtedly find themselves dealing with this frequently in their professional lives.

So it’s useful for all law enforcement officers to have a basic understanding of the types of controlled substances out there. Fortunately, there are a number of categorization systems out there to aid in understanding. We’re going to talk about one: the 7 drug categories.

The 7 drug categories

A Drug Recognition Expert (DRE) is a law enforcement officer who is trained to recognize when people have been impaired by illicit drug use. They use a categorization system that divides controlled substances into seven basic categories.

Note that these categories are divided by how the drug operates and affects the person using it, rather than by the drug’s potential to trigger addiction or its danger/potency.

Central nervous system (CNS) depressants

A CNS depressant is a substance that depresses, or slows down, the user’s system. This includes alcohol, barbiturates, and a number of anti-depressants (such as Paxil or Zoloft) and anti-anxiety tranquilizers (such as Xanax, Valium, Prozac, and Thorazine).

You’ll notice that many of these are legal, prescription drugs that a patient could get from a pharmacy; drug abuse, of course, doesn’t limit itself to illegal drugs! Effects of using these drugs can include pain relief, anxiety relief, relaxation, and even euphoria, explaining their appeal to users. They also have effects on the body such as lowered blood pressure, depressed respiration, memory/cognitive impairment, and ataxia, which is a lack of voluntary muscle coordination.

Central nervous system (CNS) stimulants

A CNS stimulant is a drug that, as the name suggests, overstimulates the user’s body. These can include a prescription drug, but the most widely known examples of CNS stimulants are drugs such as cocaine, crack cocaine, methamphetamine, and other amphetamines.

While these drugs can have medicinal uses-methamphetamines, for example, can be used to treat ADHD and obesity, although the benefits of such treatment may not outweigh the risks they are most often recreational drugs, being abused by users. Some users seek out these drugs for what appears to be their positive effects: increased ability to focus and elevated mood. However, the list of negative side effects is lengthy: accelerated heart rate, elevated blood pressure, paranoia, psychosis, and suicide ideation. Long-term use can also have negative effects on the body, leading to strokes or cardiac arrest. These drugs have a high addiction liability; with cocaine, for example, a single dose can induce tolerance to the effects of the drug.


A hallucinogen, as you might guess from the name, is a drug that causes someone to hallucinate. If a substance causes a “trip,” it’s a hallucinogen. This category includes drugs like LSD, ecstasy, and peyote. Many designer drugs are designed to mimic the effects of hallucinogens.

Hallucinogens fall into a few different categories, the most popular of which is psychedelics. Psychedelics are the “classical hallucinogens”-LSD and substances with similar effects-that alter perception (the name comes from the Greek for “mind-opening,” which is connected to the idea that these drugs “expand or open the mind”).

Hallucinogens tend to have a lower addiction liability than some of the other drugs on this list and many hallucinogens do not lead to overdoses, but that doesn’t mean they are harmless. Hallucinogen persisting perception disorder (HPPD) can occur, causing users to perceive visual hallucinations long after taking hallucinogens. There have been a number of reported deaths when the use of hallucinogens caused users to get into fatal accidents.

Dissociative Anesthetics

Dissociative anesthetics are in some ways closely related to hallucinogens. Dissociatives are sometimes considered a category that falls under the larger umbrella of hallucinogens; you’ll sometimes see drugs such as PCP categorized as “dissociative hallucinogens.” This is a category of controlled substances that, as the “anesthetic” in the title suggests, inhibits pain (or cuts off the brain’s perception of that pain). This category includes PCP, dextromethorphan, and ketamine.

Drugs that fall into this category cause a dissociative state, where the user feels detached from the environment and themselves; they often produce hallucinogenic, analgesic, amnesiac, and anesthetic effects. Drugs that fall into this category can have a high potential for causing addiction as well as a variety of negative effects. PCP can lead to comas, seizures, paranoia, violent behavior, and an increased risk of suicide, while accidental poisonings and respiratory failure have occurred from ketamine use. One psychedelic researcher, D.M. Turner, drowned in his bathtub after taking ketamine.

Narcotic Analgesics

Narcotic analgesics refer to a variety of opioids, many of which are used medicinally as a pain reliever but that are highly addictive and often abused. Controlled substances that fall into this category include opium, heroin, codeine, morphine, and prescription pain medications such as Vicodin and OxyContin.

These substances relieve pain and induce euphoria for the users. They are a dangerous combination of being readily available and highly addictive, which makes them a particularly alarming category of controlled substances. The current opioid epidemic in the United States is generally felt to have been caused by doctors over-prescribing opioid pain medications in the 1990s, leading to drug abuse, dependencies, and addictions in patients. Today, tens of thousands of Americans die from narcotic analgesic abuse every year.


Inhalants differ from many of the other categories on this list because they are categorized less by their effect than by their method of use: inhalation of fumes. The substances that fall on this list are generally not illegal; they are found in household or industrial substances and items, such as rubber cement, permanent markers, paint thinner, aerosol cans, and more. Medical anesthetics such as nitrous oxide (laughing gas) can also fall into this category.

As mentioned, the effects can vary: some are depressants, some are stimulants, some are hallucinogens, and others are dissociatives. Whatever the effect, the mundane nature of these substances doesn’t make them less dangerous. Users have died from lack of oxygen, cardiac arrest, pneumonia, and aspiration of vomit. Long-term use can lead to brain damage. Inhalants are unique (and especially dangerous) in that they are particularly popular in younger people and children; the National Institute on Drug Abuse states that inhalants are “the only class of substance used more by younger than by older teens.”


Cannabis, which is the scientific name for marijuana, is the final item on this list. Marijuana comes from a plant native to central Asia and has been used for recreational, medicinal, and entheogenic purposes for many years. The debate has long raged over whether marijuana should be outlawed; in recent years, some countries have started legalizing it. It’s still federally illegal in the US but has been legalized in eighteen states, two territories, and the District of Colombia. More states have legalized it for medicinal use (medical marijuana is sometimes prescribed for nausea, vomiting, and chronic pain).

Marijuana is used because it causes euphoria, altered states of mind, and relaxation. There is also a perception that marijuana is quite safe and difficult, if not impossible, to overdose on. This is, however, not an accurate assumption. Marijuana use can cause anxiety, delusions, paranoia, hallucinations, and psychosis. Use among the young-or use by pregnant mothers-can cause decreased mental ability and behavioral problems. Marijuana impairs driving ability and is associated with vehicle crashes, and marijuana use results in more than 1.5 million ER visits each year in the US. It is uncommon for adults to overdose on marijuana but is more likely in children, and child deaths associated with cannabis have been reported.

Controlled substance schedules

You may have heard of controlled substance schedules and wonder how they tie into the 7 drug categories. It is actually an entirely separate drug classification scheme, created by the US Controlled Substances Act in 1970.

In this scheme, there are five “schedules,” or classifications, of controlled substances. Rather than being classified by their effect or their method of use, drugs are classified according to three criteria: their potential for abuse, whether there’s a medical use for it, and its safety/potential for addiction. Here’s a brief overview:

Schedule I Drugs

These drugs have a high potential for abuse and no accepted medical purpose; they are considered unsafe for use, even with a doctor’s supervision. This includes LSD, heroin, and ecstasy.

Schedule II Drugs

These drugs also have a high potential for abuse; they may have an accepted medical use, but are still considered very dangerous. This includes cocaine, methamphetamines, and some narcotic analgesics such as Vicodin, OxyContin, and fentanyl.

Schedule III Drugs

These drugs have a medium potential for abuse, have an accepted medical use, and are considered less dangerous. They have a moderate potential for physical addiction. This includes ketamine, anabolic steroids, and products with less than 90 milligrams of codeine per dosage unit.

Schedule IV Drugs

These drugs have a moderate potential for abuse, have an accepted medical use, and could lead to moderate addiction. This includes many prescription drugs, such as Xanax, Ambien, and Valium.

Schedule V Drugs

These drugs have the lowest potential for abuse and would lead only to mild addictions. It includes cough syrups with codeine, such as Robitussin A-C, and prescription drugs such as Lyrica.


We hope this article has been useful in giving you frameworks with which to understand the controlled substances you might run into on the job. Understanding what’s out there is an important part of being prepared, and being prepared is an important part of making a real difference in your community.

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