Hallucinogens: Definition, Short & Long Term Effects, Risks & Addiction

What Are Hallucinogens?

Hallucinogens are psychedelic drugs, meaning they alter your perception of the world, your emotions, and your brain functions. Drugs like PCP, mescaline, peyote, ecstasy, and even marijuana are considered hallucinogens because they can cause you to hallucinate—you may see things that aren’t really there.

Two of the most widely used hallucinogens in North America are LSD (“acid”) and Psilocybin (“magic mushrooms” or “shrooms”). LSD stands for lysergic acid diethylamide, and was originally found in lysergic acid, a chemical in a fungus that grows on some grains, like rye. However, most LSD is now made in illegal labs. In its pure form, LSD is a white powder. It’s commonly sold in tablets or capsules, or in liquid form, which is dabbed onto blotting paper to be placed in the mouth. The blotting paper is often decorated with colourful designs. LSD can also be inhaled or injected.

Psilocybin is derived from the chemical psilocybe, found in certain species of mushrooms or fungi. It usually comes in the form of dried mushrooms, which can be eaten raw, baked into food to be eaten, or brewed into a tea. Hallucinogens have, for thousands of years, been taken during religious and spiritual rituals. Peyote continues to be used in the Native American Church in the United States today. However, these uses of hallucinogens are very different from the way these drugs are used today by the average person. Most people who try hallucinogenic drugs do not use them repeatedly, and the vast majority voluntarily chooses to never use them again.

What It Does

The hallucinogenic chemicals in LSD and psilocybin are closely related and affect you similarly. These drugs act on serotonin, an important chemical in your central nervous system, altering your thought processes, mood, perception, and your five senses.

LSD takes effect within 30 to 90 minutes, and can last up to 12 hours or more. Psilocybin acts a bit faster, within about half an hour, and lasts for two or more hours.

Short Term Effects

Hallucinogens affect all of your senses, but in particular your vision and hearing. You may see and hear things differently than they are (for example, colours may seem brighter and richer, and sounds sharper), and you may even have visions of things that aren’t there at all (hallucinations). You might experience synesthesia, which means you believe you can “hear colours,” or “see sounds.” Some people find these changes in perception pleasant. These drugs also alter your sense of time and space. Hallucinogens may also give you a feeling of relaxed well-being, happiness, love for those around you, and may make you feel as though you have great insight into the world, your life, and yourself.

Many people find altered perception and hallucinations frightening and disturbing. Some people experience the hallucination of spiders or insects crawling all over their skin, and others have described their altered perceptions as feeling they were “going crazy.” The effects of hallucinogens are very unpredictable, and can vary each time you take a hallucinogen, so you never know what kind of experience you’ll have. The effects depend on how much of a drug you take, your size and weight, whether you’re mixing a hallucinogen with other drugs or alcohol, as well as your state of mind and your expectations of the experience.

It’s also possible to experience a “bad trip,” in which the entire time you’re high, you feel an intense sense of panic and fear. After a bad trip, the anxiety and paranoia can stay with you for days, weeks, and even months. Hallucinogens may also give you a loss of appetite, a loss of coordination, paranoia, confusion, anxiety, chills, numbness, and muscle weakness. Psilocybin has been known to cause severe stomach pain, and sometimes nausea and vomiting. In high doses,

LSD can cause seizures. It’s very dangerous to take hallucinogens when taking other drugs, including alcohol. Combining them with another drug makes it that much harder to know what kind of physical and psychological effects your body and mind will experience.

There are no reported deaths from the direct effects of LSD or psilocybin. However, the total lack of perception of the world around you can lead to very risky behaviour. Many fatalities have been reported of people who were high on LSD and had an accident. People who take LSD sometimes become suicidal. Because your sense of sight and your perception are so impaired, it’s very dangerous to drive after using a hallucinogen.

Hallucinogens can also make you feel like you’re observing yourself from a distance. This means that when you take a hallucinogen, you’re less able to make conscious and informed decisions about any risky activity, including sex.

Because LSD is illegally prepared in labs, it’s impossible to know what you’re really taking, and how much. This makes your experience that much harder to predict. Psilocybin also comes with risks—many mushrooms are poisonous, and can be deadly. It’s illegal to possess or sell LSD or psilocybin in Canada. Punishment can come in the form of a minimum $1000 fine, and/or a prison sentence.

Long Term Effects

Regular LSD use may give you flashbacks, which can cause you problems years later. A flashback is when, days, weeks, or even years later, you re-experience the effects of LSD, usually for one or two minutes. You may hallucinate again, or may have your vision and thought processes temporarily altered. Flashbacks are often triggered by stress, fatigue, or other drug use.


It is believed that LSD can do long-term damage to your memory and ability to concentrate.

Right now, there is no conclusive evidence that Ecstasy is physically addictive. However, studies show that it is possible to become psychologically dependent on Ecstasy. This means you may find yourself putting Ecstasy use above friends, family school, work, and other things in your life that are important to you.

Reducing The Risks

• If someone is experiencing a “bad trip,” don’t leave them alone. Make sure they are safe and comfortable, and that they’re not able to hurt themselves.
• If someone you know is going to take a hallucinogen be sure a plan is in place in case something goes wrong – know the address of your location, and make sure you have access to a phone so you can dial 911.
• It is very dangerous to drive after taking a hallucinogen.
• Don’t inject LSD. Any needle use greatly increases the chance of acquiring HIV or other diseases.

Bet You Didn’t Know

Over the last hundred years or so, some psychologists and therapists have believed hallucinogens to be a possible treatment for psychiatric disorders. However, no study has shown that there is a medical use for these drugs. In fact, it’s quite the opposite: regular use of LSD has been linked to chronic depression.

Thought Questions

1. Though hallucinogens are not physically addictive, they are known to create psychological dependence.
What are some ways in which a dependence on hallucinogens might affect your life?
2. Do you believe it’s all right to use hallucinogens in spiritual and religious practices? Why, or why not?


LSD/Hallucinogens. Drug Info Clearinghouse, Australia, 2003.
Beyond the ABCs: Hallucinogens. Alberta Alcohol and Drug Abuse Commission, 1999.
Hallucinogens and Dissociative Drugs. Research Report Series, National Institute on Drug Abuse, 2001.