Hallucinogens: What Are They?

People begin to abuse illicit drugs for a wide range of reasons. Some choose drugs that will relax them, like opiates or alcohol, while others select stimulant drugs, like cocaine or methamphetamine. Another class of drugs that people choose to abuse for recreational purposes is the hallucinogen class – drugs that make people see, hear, and otherwise sense things that aren’t really there.

While some people believe that hallucinogens and the “trips” they take users on are safe compared to other drugs, there are a number of risks and negative effects that can occur from using hallucinogens. Many of these negative effects can continue long after hallucinogen use has stopped. For this reason, it’s helpful to understand what hallucinogens are and how they work when trying to help someone who may be struggling with hallucinogen abuse or addiction.

General Overview

Hallucinogens are drugs used specifically to immerse the user in fantasy experiences or hallucinations; in other words, they cause the person to see, hear, feel, and otherwise experience things that aren’t actually present. Use of hallucinogens to achieve this state is often called “tripping,” because this type of drug use can cause the individual to feel that the body has been left behind and the spirit is encountering these visions or experiences on another plane.

Hallucinogens are used for a number of reasons, including spiritual or religious ceremonies in which visions are sought as part of a specific ritual; natural forms of these drugs found in plants have been used for this purpose by indigenous peoples for thousands of years. However, in modern times, these drugs are often applied to a party-going experience in an attempt to make the lights, sounds, and other experiences on the club scene more intense.

Whatever the reason for using hallucinogens, it is important to understand what they are doing to the body and brain to cause the experiences that the users seek. These physical and mental effects can result in a number of problems, including the potential for addiction.

What Hallucinogens Do in the Brain

Hallucinogens: What Are They?

While there are multiple different kinds of hallucinogens, they basically all affect one of two pathways in the brain. The first is the serotonin pathway, and the second is the glutamate system.

Serotonin is a chemical that regulates many of the body’s basic functions, from mental cognition and thought processes to digestion and sleep patterns. According to Psychology Today, hallucinogens like LSD that interact with this system stop the activity of serotonin – an event that also occurs when a person is asleep and dreaming. While the dreamlike visions created by use of these hallucinogens is similar to the way dreaming occurs during sleep, there is little understanding of how these hallucinogens actually work. In fact, there could be a number of other systems involved. However, because serotonin affects so many other functions of the body, hallucinogen use can disrupt many of those functions by interfering with the pathway, including causing problems with:

  • Sleep patterns
  • Heart rate
  • Digestion (nausea or vomiting)
  • Cognitive capabilities
  • Perception of sensory input or time


Glutamate is a chemical that facilitates the brain’s ability to send messages back and forth through the body, and it is important in learning and memory. According to a study from the Industrial Psychiatry Journal, this chemical is suppressed by the use of hallucinogens like ketamine, which can result in hallucinations. Nevertheless, the full mechanism through which this occurs is not understood at this time.

Other brain chemical pathways affected by hallucinogens include the dopamine and GABA systems, both of which are implicated in the development of substance use disorders such as addiction.

Types of Hallucinogens

There are a number of different types of hallucinogens that come from different origins and that are used in different circumstances, from serious religious and ceremonial uses to recreational pursuits. No matter why or how they are used, or which parts of the brain they act on, these drugs create similar basic responses in the body as described above and carry many of the same risks described below.

  • LSD: Probably the most well-known hallucinogen, LSD affects the serotonin system. According to the National Drug Intelligence Center, LSD – an acronym for lysergic acid diethylamide – is a synthetic drug that has been abused since about the 1960s. When used, the drug can make the individual feel disconnected from the self and experience distortions of time. These delusions and visions can last up to 12 hours after initial use of the drug. The liquid is often applied to sugar cubes or paper, or it is contained in small breath freshener squeeze bottles.
  • PCP (angel dust): The drug phencyclidine, also known as PCP, was formerly used as a potent anesthetic, according to the National Traffic Safety Administration. It is a Schedule II controlled substance, because it does have some medical use; however, veterinarians only rarely use it as an animal tranquilizer today. A crystalline powder, this synthetic drug is usually found in pill form; it can also be smoked or injected. It acts on the glutamate system for its hallucinogenic effects, and it also works as a sedative.
  • MDMA (ecstasy, Molly): This drug has become popular because, along with the intense sensory response, the drug creates a sense of warmth, empathy, and happiness in the user. Combining the effects of a hallucinogen with those of a stimulant, as described by the National Institute on Drug Abuse, this drug is often used at parties to boost the atmosphere and release inhibitions. It is usually taken as a pill, but it can also be snorted as a powder or swallowed in liquid form. It affects the serotonin system, as well as the norepinephrine system – the latter is how it has its stimulant effect.
  • Ketamine (vitamin K): Originally developed as a strong, dissociative anesthetic and used in wartime for battlefield surgery, ketamine creates a trancelike state in the brain through the glutamate system. According to the DEA (CESAR), ketamine works by making the person feel disconnected from the body and from the surrounding environment. This effect can go so far as to make the individual unable to move, which makes ketamine a drug that is sometimes used in sexual assault. It is a popular drug on the club scene, where its dissociative effects can create hallucinations and euphoria in the party atmosphere.
  • DMT (ayahuasca): DMT is a chemical compound found in a number of plants around the world, particularly some that are found in the Amazon basin of South America. It is also potentially one of the oldest substances to have been used for hallucinatory effect, chiefly to facilitate spiritual or religious experiences, and it is often incorporated into a mixture called ayahuasca. Today, the drug can also be synthesized in a lab. Trips on DMT have been described as feeling transcendent, or connecting the user with the universe or a higher power. According to the Journal of Psychopharmacology, DMT has the highest percentage of new users compared to other hallucinogens, and it is continuing to grow in popularity as a recreational drug.
  • Peyote (mescaline): Another natural hallucinogen, peyote is a type of spineless cactus found in Mexico and the southwestern US. For thousands of years, it has been used in religious rituals and ceremonies by Native American peoples to induce visions and create spiritual experiences. The active substance in peyote – mescaline – affects the serotonin system in the brain, creating hallucinations and expansive sensory experiences. This drug is legal only for use by members of Native American religious groups that include the Native American Church, as defined by the American Indian Religious Freedom Act of 1994. Otherwise, it is a Schedule I controlled substance, with no known medical use.
  • Psilocybin (magic mushrooms): This substance, found in various types of fungi, like mushrooms, is yet another serotonin-acting hallucinogen. As described by Live Science, the action of the drug seems to create connections between areas of the brain that would not normally be linked. This results in a dreamy effect that users describe as leaving them feeling unified with nature and aware of something larger than themselves. While these psychedelic substances have been used for centuries, their popularity in the last several decades is attributable to awareness of the drug that was aroused in the 1960s.

Prevalence of Hallucinogen Use

Prevalence of Hallucinogen UseHallucinogens are used by approximately 15 percent of people 12 and older over the course of their lives. On the other hand, according to the 2014 National Survey on Drug Use and Health, 1.7 percent of people report having used a hallucinogen within the past year.

The most frequently used hallucinogen is LSD, with 9 percent of people using it over the course of their lifetime, and 0.5 percent engaging in use within the previous year. Ecstasy is next, at 6.6 percent lifetime and 0.9 percent past-year prevalence, and PCP is generally used by 2.4 percent of people over their lifetimes.

Physical and Psychological Risks of Use

According to the National Institute on Drug Abuse, the risks of hallucinogen abuse include:

  • Increase in circulation, heart rate, breathing, or body temperature
  • Appetite or sleep issues, weight loss, or insomnia
  • Paranoia, panic, or psychosis
  • Detachment from the self or environment
  • Memory loss
  • Depression

Another potential long-term effect is HPPD, or hallucinogen persisting perception disorder, which can result in visual and other disturbances that last long after hallucinogen use has stopped. For many, this annoyance – which can include seeing halos around objects, light trails, and fuzzy or static blurs over the environment – can become extremely upsetting and contribute to the potential for depression or suicide.

Hallucinogen Abuse

As described above, abuse of hallucinogens usually occurs in religious or spiritual rituals, or at parties. They are used either to facilitate spiritual experiences or to enhance sensory stimulation in a party atmosphere.

Many people who use hallucinogens do so in safe spaces set up to allow for a “watcher” – an individual who keeps an eye on the person who has used the drug. This is because sometimes trips can turn bad, with the hallucinogenic effects creating something more of a nightmare, rather than a dream-like state.

Bad trips last as long as the drug has an effect in the body, but there can be a challenge if the person who has used the drug begins to have flashbacks of that experience. This is another negative effect of hallucinogen use.

Treatment Options

It is possible to become addicted to hallucinogens because of the way they affect the dopamine system. Like with many other drugs, this can lead to tolerance and addiction. However, it is possible to treat this addiction through professional, research-based rehab. This includes therapies such as:

  • Medical detox, if needed
  • Behavioral therapy to learn to manage and overcome cravings
  • Family or social therapy to build the person’s support network
  • Support group participation to provide resources, shared personal experiences, and accountability
  • Aftercare to help with the transition back to daily life.

With these treatments, a person can learn to deal with the chronic nature of addiction and return to a positive life without using hallucinogens, finding meaning and purpose again in the real world.

Most health insurance plans cover addiction treatment in some capacity. Take the next step by checking your insurance coverage or call us today at to learn about our Tampa addiction treatment programs.

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