Psychoactive drugs are substances that affect the brain. The types range from heroin to caffeine. These substances can affect awareness, thoughts, mood, and behavior.

Depending on the situation, the effects of psychoactive drugs may be beneficial or harmful.

The phrase “psychoactive drug” often refers to illegal substances, such as lysergic acid diethylamide (LSD), heroin, and cocaine. However, these drugs form part of a larger category of psychoactive substances, several of which are legal.

Nicotine, alcohol, and caffeine are all types of psychoactive substances that people frequently consume. In fact, roughly 80% of adult Americans consume caffeine daily.

This article reviews the different types of psychoactive drugs and provides some examples.

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A psychoactive substance is any substance that interacts with the central nervous system. When a person uses them, it causes changes in how the brain responds to stimuli.

Their effect on the central nervous system causes an individual to experience changes, including:

  • mood changes
  • behavioral changes
  • changes in awareness
  • altered thoughts
  • changes in how they feel

These changes can be helpful or desirable, but psychoactive drugs can also yield unwanted effects.

Psychoactive drugs fall into different categories, depending on what effects the drug has on a person. These include:

  • Depressants: These drugs can calm the brain, cause sleepiness, and make a person feel relaxed. However, they can also cause nightmares, anxiety, and aggression. Alcohol is an example of a depressant.
  • Stimulants: These include drugs such as cocaine and caffeine. Stimulants can increase energy, alertness, and wakefulness.
  • Opiates: These are pain-killing drugs that increase feelings of happiness or euphoria and create a tranquilizing effect. They can lead to addiction if a person misuses them, and they include drugs such as heroin.
  • Hallucinogens: These drugs can cause a person to have hallucinations, which means they may see or hear things that are not there. They can also cause a person to perceive time differently, feel detached from their surroundings, or feel deeply insightful. LSD is an example of a hallucinogen.

There are several different examples of psychoactive substances, and they all have different effects on the body and brain.

While not all psychoactive substances are illegal, a person can misuse any of these substances.

The following are common examples of psychoactive drugs and their effects on the body.


Heroin is an illegal drug that binds to opioid receptors in the brain, causing a “rush” of pleasurable sensations.

Despite the initial feelings of euphoria, heroin can cause a slower heart rate, feelings of sleepiness, and clouded thinking. However, the physical effects of heroin, such as a slower heart rate and reduced breathing, may sometimes be life threatening.


Cocaine is a stimulant that is illegal in many countries. It can cause an immediate euphoric effect that lasts from a few minutes to about an hour.

Higher doses of this drug can cause a person to experience erratic behaviors, including violence, anxiety, panic, and paranoia. It can also lead to severe complications, including heart attacks and sudden death, potentially with a person’s first use.

Learn more about cocaine.


LSD and other hallucinogens can cause a person to experience, hear, or see things that do not exist. Some of these experiences can feel pleasurable and profound, while others can feel frightening.

LSD can also cause elevated blood pressure, sleeplessness, and dizziness.

Additionally, using LSD can lead to the development of tolerance for both the drug itself and other hallucinogens, meaning an individual needs to take higher doses to experience the same “high.”

Learn more about LSD.

Methylenedioxy-methylamphetamine (MDMA)

MDMA, also called molly or ecstasy, can have both stimulant and hallucinogen effects. Some people who use it feel increased empathy and emotional closeness, an elevated mood, and increased energy.

However, moderate use can cause irritability, depression, sleep problems, and anxiety.

Learn more about MDMA.


Amphetamines are a type of stimulant. They can come in the form of prescription medications to treat attention deficit hyperactivity disorder or narcolepsy, with the brand names Adderall or Dexedrine.

People sometimes use these as recreational drugs, as they can give a person a “rush” of euphoria and increase energy and alertness.

However, they can also cause paranoia, anger, and psychosis. High doses can cause heart failure or seizures.

Learn more about amphetamines.


Cannabis, also called weed, is a type of psychoactive drug that can have the effects of a depressant, stimulant, or hallucinogen.

This drug affects everyone differently, but common effects include an increased appetite, euphoria, and relaxation. Some people might also have altered senses, for example, seeing brighter colors.

However, some may have negative effects after taking the drug, such as feeling panic, fear, and distrust.

Learn more about cannabis.


People generally class alcohol as a depressant because it slows down a person’s thinking and responses. It can make someone feel calm, relaxed, or euphoric.

However, it can also reduce a person’s ability to think rationally and lead to impaired judgment. Over time, an individual can develop a tolerance to or dependency on alcohol.

Learn more about alcohol.


Nicotine, which people can find in smoked and chewed tobacco products, is a stimulant and depressant. Nicotine first provides a “buzz” of energy and pleasure.

However, this effect fades over time and leaves a person feeling fatigued. Their body can also become dependent on nicotine, which can lead to addiction.

Learn more about nicotine.


This is the most common form of legal psychoactive drug. Caffeine acts as a stimulant that can aid alertness.

However, it can also disrupt a person’s sleep. Like nicotine and alcohol, an individual can build up a tolerance to caffeine, which means they need to consume more to feel its effects. This can lead to dependency and withdrawal symptoms when a person stops taking it.

Learn more about caffeine.

Prescription opioids

A doctor can prescribe opioids to someone for moderate to severe pain. Common brand names of prescription opioids include OxyContin and Percocet.

They are generally safe when a person takes them as a doctor prescribes and over the short term. However, people can misuse prescription medications by:

  • taking medication that doctors have prescribed to someone else
  • taking the medication in amounts or ways other than doctors have prescribed
  • taking the medication to get high

Prescription opiates can be very harmful if someone takes them differently from how a doctor has prescribed them.

Because they cause a person’s breathing to slow, misusing them can cause hypoxia, when the brain does not get enough oxygen. This can lead to coma, permanent brain damage, or death.

Learn more about opioids.

Whether a person uses psychoactive substances as medication, recreational drugs, or as part of their daily routine, there are risks to using them. For example, all drugs can lead to dependency and addiction.

Different drugs have varying effects and risk levels associated with them. In particular, legal and illegal drugs have different levels of potential harm.

Legal psychoactive drugs

Legal drugs, such as caffeine, alcohol, nicotine, and prescription medications, tend to be safe with responsible use.

However, these drugs can still have adverse consequences with excessive or improper use. For example, it is dangerous for a person to drive while under the influence of alcohol or misuse prescription medications.

Smoking drugs such as nicotine or cannabis can also cause damage to a person’s lungs and increase the risk of several types of cancer.

Find out more about the risks of caffeine.

Learn more about the health risks of excessive alcohol consumption.

Find out more about the health risks of smoking.

Illegal psychoactive drugs

Using illegal drugs usually poses a higher risk. Because they may not undergo professional manufacturing processes in a laboratory, a person cannot be sure what ingredients an illegal drug may contain.

Illegal drugs can contain substances that are dangerous to consume. For example, some illegal drug makers mix drugs, such as heroin, cocaine, methamphetamine, and MDMA, with a powerful synthetic opioid called fentanyl.

A person who takes a drug containing fentanyl is more likely to overdose if their body does not have sufficient tolerance for strong opioids.

Additionally, some drugs, such as cocaine, have an association with potentially serious side effects, including heart attack and sudden death.

Learn how to recognize the signs of an opioid overdose.

Other common risks of psychoactive substances include:

  • addiction
  • worsening mental health issues
  • problems with memory
  • unintended weight loss
  • lung damage from smoking
  • complications in pregnancy
  • increased or decreased blood pressure
  • overdose

Help is available

Seeking help for addiction may feel daunting or even scary, but several organizations can provide support.

If you believe that you or someone close to you is showing signs of addiction, you can contact the following organizations for immediate help and advice:

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Psychoactive drugs alter the way a person thinks, acts, and feels. They often fit into one or more categories, including stimulants, depressants, opiates, and hallucinogens.

  • Stimulants may cause someone to feel a sense of euphoria, excitement, or increased energy.
  • Depressants can make people feel sleepy, relaxed, or calm.
  • Opiates can cause euphoria and have a tranquilizing effect.
  • Hallucinogens can alter a person’s senses and cause them to see or hear things that are not there.

Different drugs have varying risks, but some are common among psychoactive drugs. Some of these risks include heart issues, addiction, worsening symptoms of mental illness, and death.