Types of Drugs by Effect, Chemical Makeup & Legal Definition


Drug Classifications Based on Effect


As their name suggests, stimulants, which can also be known as “uppers,” are drugs that create stimulation or a sense of rush after taking them. Initially, people who take these kinds of drugs feel more productive, alert and excited. They may also experience an intense feeling of pleasure after taking stimulant drugs.

After continued use, people can become addicted to stimulants. They may even be unable to function on a daily basis without taking stimulants to keep awake or handle routine tasks at work or school. They often need rehabilitative or medical intervention to overcome their addictions to these types of substances.

After continued use, people can become addicted to stimulants

Stimulants come in a variety of forms and can be found in both illicit and prescription drugs. Some of the most common stimulants people can easily get addicted to include:


Depressants are the opposite of stimulants and are colloquially known as “downers.” Depending on in what form they are produced and sold, they can have a legitimate medical or therapeutic purpose, primarily in the treatment of mental illnesses like anxiety or panic disorder. They can also be used to treat sleep deprivation.

When taken incorrectly or in dosages not prescribed for the patient, depressants can become addictive and have powerful effects on people’s behaviors. People can feel sleepy, heavy and sluggish. People under the influence of high dosages of depressants are also many times unable to operate cars or other vehicles safely.

People under the influence of depressants  may be unable to operate cars or other vehicles safely.

Depressants also present a high risk of overdosing for people who abuse them. People who abuse these kinds of drugs can take too much and die from accidental overdoses. Some of the most common depressants people abuse today include:


Inhalants cover a wide range of chemicals that are abused primarily through breathing, or huffing, them into one’s body. These substances are not designed to be ingested or breathed in by people. They are legitimately sold for purposes like painting or cosmetics.

Inhalants are also some of the least studied substances that drug addicts abuse. Drug abuse experts do know that inhalants can cause a wide array of health problems, even brain and lung damage, and can also be easily overdosed on because of their chemical makeup.

Drug abuse experts do know that inhalants can cause a wide array of health problems, even brain and lung damage

These substances are also relatively easy to find in grocery stores and hardware retailers in just about every city. People who abuse them do not have to buy them from a dealer, as they would for purchasing illicit drugs like cocaine. They can simply walk into their local store and buy inhalants.

Some of the most common inhalants that are abused today include:


Hallucinogens are drugs that alter people’s sense of reality and perception. They often impact a person’s vision or sense of hearing. People who abuse them often believe they see or hear things that are not really there.

The colloquial term for the effect that hallucinogens cause is known as “tripping.” The effects of tripping can last for hours and have serious impacts on a person’s health.

Hallucinogens are not as addictive as other illicit substances like cocaine or meth. They still are illegal to abuse and can pose a serious danger to people who take them or people who encounter people tripping on these substances.

Some of the most common hallucinogens abused today are:

Drugs Classifications Based on Chemical Makeup


Alcohol is the most abused drug throughout the entire world and is legal for adults to buy, possess and consume in all 50 U.S. states. It is classified as a central nervous system depressant. Initially, it creates a feeling of relaxation and lowered inhibition. When a person is drunk from drinking too much alcohol, he or she may show impaired judgment, have slower reaction times and impaired perception.

Alcohol also damages the liver when it is consumed in high amounts. People who are addicted to alcohol are at a greater risk of illnesses like cirrhosis and liver cancer. They can also cause damage to organs like their kidneys.

Common types of alcohol are:


Cannabidoids are drugs that contain a chemical structure that is similar to THC, which is the intoxicant found in marijuana. Cannabidoids are becoming widely accepted and even legally allowable in many U.S. states. They are the second most abused substances in the U.S, right behind alcohol.

Cannabinoids are not as addictive as other illegal substances like meth or heroin. Still, they pose a risk to people’s mental and physical health when abused. They negatively impact people’s ability to think and react normally.

Cannabinoids negatively impact people's ability to think and react normally

They cause a sense of euphoria or elation when they are taken, a sensation known as a high. Some common examples of cannabidoids found today are:


Opioids are also known as opiates and present one of the most dangerous drug addictions people can succumb to today. Prescribed for people with medical conditions like chronic pain or broken bones, opioids can serve a legitimate medical purpose. When they come in forms other than prescription medications or are purposely abused to achieve a feeling of pleasure or relaxation, they can become highly addictive.

Each year, scores of people die from addictions to opioids. These drugs target receptors in a person’s brain and can act like neurotransmitters. They can also block pain signals, making them highly addictive to people who were prescribed and abuse them after surgery or other medical treatments.

Some common opioids include:


Barbiturates come from a chemical known as barbiturate acid and function by slowing down the body’s central nervous system. They were commonly used in medicine years ago and often recommended for conditions like sleep deprivation or some forms of mental illness. Hospitals still use them for anesthetic purposes.

When misused or taken in too high of doses, barbiturates pose a serious risk to the person taking them. They can gravely damage numerous systems in the human body. They are also easily overdosed on and can cause someone to die from taking them in too high of doses.

Barbiturates are often prescribed by doctors for patients with certain health conditions. Common examples include:


Benzodiazepines are commonly known by their shortened name of “benzos” and are typically prescribed to patients who suffer from mental illnesses like anxiety or panic attacks. They are also used to treat sleep disorders like insomnia.

They function in the human body by interacting with a neurotransmitters called GABA-A. Benzos affect each person taking them differently, which is why it is important for patients to remain under medical or psychiatric care to ensure they receive the right one to treat their mental or physical conditions.

When taken in too high of doses, benzos can become highly addictive. A person who abuses them can damage their own physical and mental health. Examples of benzos are:

Drug Classifications Based on Legal Definitions

Schedule V

Schedule V drugs are the lowest category of drugs in terms of addiction and risk of legal penalties for abusing them. They have a variety of legitimate medical purposes. They can be found over-the-counter or are sometimes prescribed to patients who experience relatively minor health ailments, such as stomach viruses or skin rashes.

Schedule V drugs are commonly used for purposes like anti-diarrheal, analgesic and antitussive reasons. They typically contain limited amounts of narcotics, such as codeine, in them. Substances with codeine are only available by prescription and carry with them the moderate risk of addiction to them.

Some examples of Schedule V substances are:

Schedule IV

Schedule IV drugs are also used for legitimate purposes for both mental health and physical conditions. Common reasons people may be prescribed one of the scores of Schedule IV drugs available today include being treated for chronic pain or severe depression.

Schedule IV drugs are less addictive than drugs found in Schedules I, II and III. They also carry with them lesser legal consequences if people are found to be in possession of or abusing them.

Taken in too large of dozes, Schedule IV drugs can also cause damage to systems and organs in the human body. They can impair a person’s judgment and mental health. They can also harm organs like the liver. Examples of Schedule IV drugs are:

Schedule III

Schedule III drugs carry with them a higher risk of addiction and dependency than the drugs found in Schedules IV and V. When prescribed by doctors, they serve legitimate medical and mental health purposes. They can be used to treat conditions like depression, narcolepsy, weight management and severe or chronic pain.

When taken incorrectly or in doses that are too high for what they are prescribed for, Schedule III drugs can severely impair a person’s health. They also carry with them the risk of overdosing on them. If someone is found to possess or distribute Schedule III drugs illegally, he or she could also face severe legal consequences, including jail time.

Examples of Schedule III drugs include:

Schedule II

Schedule II drugs are highly addictive and carry with them serious legal punishments if a person is found guilty of possessing or selling them illegally. They are prescribed for legitimate reasons, such as to treat severe pain after surgery or ADHD in adolescents and adults. They are also used to help people wean off addictive drugs like heroin.

People who abuse Schedule II drugs are also at an increased risk of damaging their brains and internal organs. They can also overdose on these types of substances and die from taking too high of doses.

Types of Schedule II drugs include:

Schedule I

Schedule I drugs carry with them the harshest legal penalties for abusing them. They are highly addictive, more so than the drugs found in the other four schedules. They can be prescribed to treat medical or mental health conditions like insomnia or anxiety.

Schedule I drugs carry with them the harshest legal penalties for abusing them.

They can also be illicit substances that people buy from drug dealers. They pose a grave danger to people’s health when taken without the supervision or recommendation of a psychiatrist or physician. They are also easily to overdose on because of how addictive they are. Abusers often take increasingly higher doses to get high.

Some of the more common types of Schedule I drugs include: