Drug Classification

Table of Contents

Introduction to Drug Classification

Why do you need to know about drug classification? Because drug abuse isn’t going away, and detailed information is important.

Drugs of abuse are substances that some people misuse. This can include using prescription medications or illegal drugs, taking a prescription that doesn’t belong to you in order to feel good, or taking a prescribed medication differently than a doctor intended.

Unfortunately, using drugs of abuse can eventually lead to addiction. There are various types of drugs of abuse, and there is a system of drug classification. This system divides the substances into categories and describes the effects of each classification of each drug.  Do you need treatment for drug abuse?

Drug Classification System

The drug classification system breaks drugs down into multiple categories. Some of the categories include:





Anabolic steroids

OTC drugs


Stimulant drugs include methamphetamine and cocaine, as well as prescription medications like Adderall and Ritalin, which are used to treat attention-deficit/hyperactivity disorder (ADHD). These drugs excite the nervous system and create feelings of euphoria; they also increase alertness and may lead to feelings of grandiosity. It’s possible to experience negative effects after using stimulants. These include high blood pressure, heart palpitations, or tremor.1

There are some serious consequences associated with stimulant abuse. For example, people may experience overheating, heart problems, seizures, and psychosis. In addition, people who smoke crack cocaine may develop lung problems, breathing issues, or chronic chest pain. It is possible to suffer sudden death due to heart problems as a result of stimulant abuse.1

Over time, an addiction to stimulants may develop. Addiction is more likely among people who use heavily and who smoke or inject the drugs.1 According to SAMHSA, 2 percent of people aged 12 and older had used cocaine during the last year as of 2018, and 0.7 percent had used methamphetamine. Abuse of prescription stimulants is even more common among young adults; as of 2018, 6.5 percent of those aged 18-25 had misused them within the last year.2


On the opposite end of the drug classification system are depressant drugs. Under this class are anxiety drugs called benzodiazepines and sedative drugs called barbiturates. The side effects of depressants typically include:1

Difficulty talking

Trouble understanding information

Mood swings

Memory loss

Poor judgment

Shortened attention span

Benzodiazepines and barbiturates are both potentially addictive, despite the fact that they are prescription drugs.

Alcohol is also considered a central nervous system depressant, as it increases levels of a brain chemical called GABA. This slows the nervous system and decreases levels of glutamate, which causes the nervous system to work more quickly.3 Over the short-term, people who abuse alcohol may show obvious signs of intoxication, including:

Blurred vision

Memory issues

Slurred speech

Difficulty walking

Over the long-term, alcohol abuse can lead to serious consequences. One serious long-term consequence is brain shrinkage, which creates problems with learning and memory.4 Alcohol abuse is unfortunately common, with 10.1% of people aged 18-25 and 5.1 percent of those 26 years old and older meeting criteria for an alcohol use disorder in 2018.3


Opioids include illicit drugs like heroin, as well as prescription painkillers, such as oxycodone, hydrocodone, morphine, and fentanyl. After use, these drugs create feelings of euphoria and result in other side effects, such as dry mouth, itching, nausea, vomiting, and slowed breathing and heart-rate. Long-term abuse of opiates can result in serious side effects, such as:

Liver or kidney disease


Collapsed veins


Infections in the heart

Opioids are very addictive, and overdose is a potential consequence of ongoing opiate misuse, regardless of whether it is heroin or prescription opiates.5

In 2018, 3.7% of the U.S. population aged 12 and older misused opiates. Of those who abused opiates, the majority (97.1%) abused prescription painkillers.3


Marijuana falls within the cannabinoid drug classification. Marijuana tends to cause feelings of euphoria, along with relaxation. Some people also report decreased energy and ambition with marijuana use. Marijuana is known to increase appetite, create a feeling of relaxation, impair concentration, and slow reaction time. Experts report that most people use marijuana only from time-to-time, but the drug can become addictive and create consequences with repeated, heavy use.4

Using high doses of marijuana over time can create brain changes and memory problems, especially among those who begin using it as a teenager. In addition, smoking large amounts of marijuana can create respiratory problems, such as coughing, wheezing, and bronchitis. Marijuana can be especially harmful to people with schizophrenia. It may create feelings of panic and paranoia and can result in psychosis in those who are vulnerable to conditions, such as schizophrenia.3

Marijuana use is highly common in the United States. In 2018, 22.1% of people aged 18-25 and 8.6% of those 26 and older reported using the drug within the past month. In addition, 6.7% of those aged 12-17 had used it in the last month.4


Among the hallucinogen drug classification are drugs like LSD, psilocybin, and mescaline. LSD is derived from a fungus; psilocybin is found in mushrooms, and mescaline comes from a cactus plant. As their name might suggest, these drugs result in hallucinations, changes in perception, poor judgment, and feeling detached from the self. Hallucinogens can be particularly dangerous because reactions to this drug classification can be unpredictable.4

People typically refer to the high from hallucinogens as a “trip.” Many people feel euphoria with hallucinogen abuse, but some people may become depressed. Senses are heightened when a person uses hallucinogens, and some people may see and hear things that are not actually present.4

People can develop a tolerance for hallucinogens, and over time they may have flashbacks of using these drugs. During flashbacks, the perceptual distortions associated with hallucinogen use may reappear. For instance, people may see visual illusions or have a distorted perception of time or space after one of these flashbacks. These flashbacks tend to subside after a year, but some people may continue to experience them for several years after stopping hallucinogen abuse.4

According to SAMHSA, 3.5% of those aged 18-25 had used LSD within the past year, as of 2018. Use drops off among those aged 26 and older, falling to 0.4% in this age group.3

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Anabolic Steroids

Unlike other substances in the drug classification system, people don’t really use anabolic steroids to get high. Instead, these drugs are typically used to enhance physical appearance and athletic performance. For example, steroids are known to increase muscle mass and improve strength, so athletes and bodybuilders may use them.4

Doctors also prescribe steroids to treat low testosterone levels in men or to treat cases of muscle wasting. Even though these drugs have legitimate medical uses, they are widely abused, especially in certain groups. For instance, anywhere from 6% to 11% of high school boys abuse anabolic steroids, and around 2.5% of high school girls have used them.4

Ongoing steroid use can lead to addiction, and people who stop using these drugs may experience withdrawal. Withdrawal from steroids can include:5

Mood swings



Low appetite

Sleep problems

Decreased sex drive

Suicidal behavior

There are also negative side effects associated with continued use of anabolic steroids, including reduced sperm count, balding, breast development, and infertility among men. Women who abuse steroids may experience facial hair growth, deepened voice, and even male pattern baldness. Steroid use is also linked to aggression, extreme anger and mood swings, irritability, delusions, and poor judgment. There are also some serious health risks associated with steroid use, such as liver damage, kidney failure, high blood pressure, stroke, and heart attack.5

OTC Drugs

In addition to the illicit and prescription drugs included in the drug classification system, some people may abuse over-the-counter (OTC) medications. One popular drug of abuse in the OTC category is dextromethorphan (DXM), which is used to treat cough. When people take more than the recommended dose of this OTC medication, it can cause euphoric feelings, slurred speech, elevated heart rate and blood pressure, dizziness, nausea, and vomiting.5

People may also abuse the anti-diarrheal drug Imodium because it can produce euphoria in high doses. Despite being a common OTC medication, abusing Imodium in large quantities can be dangerous. For example, high doses of the drug can cause fainting, stomach pain, loss of consciousness, cardiovascular problems, and kidney failure.5

Substance Use Disorder

“Substance use disorder” is the clinical term used by doctors and addiction treatment professionals to describe a diagnosable condition that involves the chronic misuse of drugs or alcohol. A person can develop a substance use disorder after using any of the drugs of abuse.

A substance use disorder is the official term for an addiction to drugs or alcohol. It involves symptoms such as failing to complete duties at work or school because of substance abuse, continuing to use drugs despite health or relationship problems, having a desire to reduce drug use and developing withdrawal symptoms when not using the drug.6

According to the Substance Abuse and Mental Health Services Administration (SAMHSA), 7.8% of the American adult population had a substance use disorder in 2018.2

During the same year, 38.3% of those with a substance use disorder used illicit drugs, whereas 74.5% abused alcohol. In addition, 12.9% struggled with both drug and alcohol abuse.6

Treating Substance Use Disorders

OTC drugs, prescription medications, and illegal drugs can all be misused, potentially leading to consequences like an addiction. If you feel that you have lost control over your drug use and want to stop but are not able to do so on your own, it is possible that you have developed a substance use disorder. In this case, treatment can help you live a drug-free life.

Treatment will vary based upon what substance in the drug classification system you are using. For example, if you have developed a substance use disorder linked to opiates or alcohol, you may first need to go through detox to help you get through withdrawal symptoms. With opiate addiction, you may receive medications like buprenorphine or methadone to help during withdrawal.5

With any substance use disorder, behavioral therapies will likely be necessary to treat the disorder. These therapies will often include both group and individual counseling, which can occur on either an inpatient or outpatient basis. Specific therapies may include cognitive-behavioral therapy (CBT), where you can learn how to overcome negative thinking patterns and coping strategies that contribute to addiction. For example, if you have convinced yourself that you cannot get through life or manage stress without alcohol, CBT can teach you new ways of thinking and coping.

No matter what type of substance use disorder you’re struggling with, there is treatment available. Reach out to an addiction professional today to begin your journey toward healing and recovery.