HALLUCINOGENS AND 

DISSOCIATIVE DRUGS

Including LSD, PCP, Ketamine, Psilocybin,

Salvia, Peyote, and Dextromethorphan

Research Report Series

U.S. Department of Health and Human Services | National Institutes of Health

from the director:

Hallucinogens and dissociative drugs—

which have street names like acid, 

angel dust, and vitamin K—distort the 

way a user perceives time, motion, 

colors, sounds, and self. These drugs 

can disrupt a person’s ability to think 

and communicate rationally, or even to 

recognize reality, sometimes resulting 

in bizarre or dangerous behavior. 

Hallucinogens such as LSD and psilocybin 

cause emotions to swing wildly and 

real-world sensations to appear unreal, 

sometimes frightening. Dissociative 

drugs like PCP, ketamine, DXM, and Salvia 

divinorum may make a user feel out of 

control and disconnected from their body 

and environment. 

In addition to their short-term effects 

on perception and mood, hallucinogenic 

drugs are associated with psychoticlike episodes that can occur long after 

a person has taken the drug, and 

dissociative drugs can cause respiratory 

depression, heart rate abnormalities, and 

a withdrawal syndrome. The good news is 

that use of hallucinogenic and dissociative 

drugs among U.S. high school students, 

in general, has remained relatively low in 

recent years. However, the introduction 

of new hallucinogenic/dissociative drugs, 

such as salvia, is of particular concern. In 

fact, salvia is currently the most widely 

used drug in this class. 

NIDA research is developing a clearer 

picture of the dangers of hallucinogenic 

and dissociative drugs. We have compiled 

the scientific information in this report to 

inform readers and hopefully prevent the 

use of these drugs. 

Nora D. Volkow, M.D. 

Director 

National Institute on Drug Abuse

Long-Term Effects of 

Hallucinogens

See page 5.

What Are 

Hallucinogens and 

Dissociative Drugs? 

continued inside

Hallucinogens are a class of drugs that cause hallucinations—profound 

distortions in a person’s perceptions of reality. Hallucinogens can be found in 

some plants and mushrooms (or their extracts) or can be man-made, and they 

are commonly divided into two broad categories: classic hallucinogens (such as LSD) 

and dissociative drugs (such as PCP). When under the influence of either type of drug, 

people often report experiencing rapid, intense emotional swings and seeing images, 

hearing sounds, and feeling sensations that seem real but are not. 

While the exact mechanisms by which hallucinogens and dissociative drugs cause their 

effects are not yet clearly understood, research suggests that they work at least partially 

by temporarily disrupting communication between neurotransmitter systems throughout 

the brain and spinal cord that regulate mood, sensory perception, sleep, hunger, body 

temperature, sexual behavior, and muscle control. 

Psilocybin mushrooms, LSD, and Salvia divinorum are commonly 

used hallucinogenic and dissociative compounds
Research Report Series

Classic Hallucinogens*

LSD (d-lysergic acid 

diethylamide)—also 

known as acid, 

blotter, doses, hits, 

microdots, sugar 

cubes, trips, tabs, 

or window panes—is one of the 

most potent mood- and perceptionaltering hallucinogenic drugs. It is a 

clear or white, odorless, water-soluble 

material synthesized from lysergic 

acid, a compound derived from a rye 

fungus. LSD is initially produced in 

crystalline form, which can then be 

used to produce tablets known as 

“microdots” or thin squares of gelatin 

called “window panes.” It can also 

be diluted with water or alcohol and 

sold in liquid form. The most common 

form, however, is LSD-soaked paper 

punched into small individual squares, 

known as “blotters.” 

Psilocybin 

(4-phosphoryloxyN,N-dimethyltryptamine)—also 

known as magic 

mushrooms, shrooms, 

boomers, or little smoke—is extracted 

from certain types of mushrooms 

found in tropical and subtropical 

regions of South America, Mexico, 

and the United States. In the past, 

psilocybin was ingested during 

religious ceremonies by indigenous 

cultures from Mexico and Central 

America. Psilocybin can either be 

dried or fresh and eaten raw, mixed 

with food, or brewed into a tea, and 

produces similar effects to LSD. 

Dissociative Drugs

PCP 

(Phencyclidine)—

also known as 

ozone, rocket fuel, 

love boat, hog, 

embalming fluid, or 

superweed—was originally developed 

in the 1950s as a general anesthetic 

for surgery. While it can be found 

in a variety of forms, including 

tablets or capsules, it is usually sold 

as a liquid or powder. PCP can 

be snorted, smoked, injected, or 

swallowed. It is sometimes smoked 

after being sprinkled on marijuana, 

tobacco, or parsley.

Ketamine—also 

known as K, 

Special K, or 

cat Valium—is 

a dissociative 

currently used as 

an anesthetic for humans as well as 

animals. Much of the ketamine sold 

on the street has been diverted from 

veterinary offices. Although it is 

manufactured as an injectable liquid, 

ketamine is generally evaporated 

to form a powder that is snorted 

or compressed into pills for illicit use. 

Because ketamine is odorless and 

tasteless and has amnesia-inducing 

properties, it is sometimes added to 

drinks to facilitate sexual assault.

DXM 

(Dextromethorphan)—

also known as 

robo—is a cough 

suppressant and 

expectorant ingredient 

in some over-the-counter (OTC) cold 

and cough medications that are often 

abused by adolescents and young 

adults. The most common sources of 

abused DXM are “extra-strength” 

cough syrup, which typically contains 

around 15 milligrams of DXM per 

teaspoon, and pills and gel capsules, 

which typically contain 15 milligrams 

of DXM per pill. OTC medications 

that contain DXM often also contain 

antihistamines and decongestants. 

Salvia divinorum—

also known as 

diviner’s sage, Maria 

Pastora, Sally-D, 

or magic mint—is a 

psychoactive plant 

common to Southern Mexico and 

Central and South America. Salvia 

divinorum (salvia) is typically ingested 

by chewing fresh leaves or by drinking 

their extracted juices. The dried leaves 

of salvia can also be smoked or 

vaporized and inhaled.

2 NIDA Research Report Series

Common 

Hallucinogens and 

Dissociative Drugs

*In this report, the term “hallucinogen” will refer to the classic hallucinogenic drugs LSD and Psilocybin.
While regular use of hallucinogenic and dissociative drugs in general has 

remained relatively low in recent years, a recent study reported that the United

States ranks first among 36 nations in the proportion of high school students 

ever using LSD or other hallucinogens in their lifetime (6 percent versus 2 

percent in Europe).3

How Widespread 

Is the Abuse of 

Hallucinogens and 

Dissociative Drugs?

According to the 2012 National 

Survey on Drug Use and Health, 

more than 180,000 Americans aged 

12 and older reported current (pastmonth) use of LSD and 32,000 

reported current use of PCP.1 New 

hallucinogenic/dissociative drugs 

have also emerged on the scene in 

recent years. Salvia, historically used 

by indigenous tribes of Southern 

Mexico during religious rituals, has 

replaced LSD and PCP as the most 

commonly used hallucinogenic drug. 

In fact, past-year use of salvia among 

the nation’s 12th-grade students is 

more than 1.5 times that of LSD (3.4 

percent versus 2.2 percent) and almost 

5 times that of PCP (3.4 percent 

versus 0.7 percent).2

Why Do People Take Hallucinogenic 

or Dissociative Drugs? 

Hallucinogenic and dissociative drugs have been used for a variety of reasons.4,5 

Historically, hallucinogenic plants have been used for religious rituals to induce 

states of detachment from reality and precipitate “visions” thought to provide 

mystical insight or enable contact with a spirit world or “higher power.” More 

recently, people report using hallucinogenic drugs for more social or recreational 

purposes, including to have fun, help them deal with stress, or enable them 

to enter into what they perceive as a more enlightened sense of thinking or 

being. Hallucinogens have also been investigated as therapeutic agents to treat 

diseases associated with perceptual distortions, such as schizophrenia, obsessivecompulsive disorder, bipolar disorder, and dementia.

Street Names for Select Hallucinogenic and Dissociative Drugs

LSD

• acid

• blotter

• dots

• sugar

• trips

• window pane

Ketamine

• vitamin K

• bump

• green

• K/Special K

• purple

• super acid

PCP

• angel/angel dust

• boat/love boat

• peace

• killer weed

• super grass

• ozone

NIDA Research Report Series 3
How Do Hallucinogens (LSD and 

Psilocybin) Affect the Brain and Body?

How Do Hallucinogens Work? 

Classic hallucinogens are thought to produce their perception-altering 

effects by acting on neural circuits in the brain that use the neurotransmitter 

serotonin.6-9 Specifically, some of their most prominent effects occur in the prefrontal 

cortex—an area involved in mood, cognition, and perception—as well as other 

regions important in regulating arousal and physiological responses to stress and 

panic.

Short-Term 

General Effects of 

Hallucinogens

Sensory Effects

•	 Hallucinations, including 

seeing, hearing, touching, or 

smelling things in a distorted 

way or perceiving things that 

do not exist

•	 Intensified feelings and 

sensory experiences (brighter 

colors, sharper sounds)

•	 Mixed senses (“seeing” 

sounds or “hearing” colors)

• Changes in sense or 

perception of time (time goes 

by slowly)

Physical Effects

•	 Increased energy and 

heart rate

•	 Nausea

†

Misidentification of poisonous mushrooms resembling psilocybin could lead to unintentional, potentially fatal poisoning

What are the ShortTerm Effects of 

Hallucinogens? 

Ingesting hallucinogenic drugs 

can cause users to see images, hear 

sounds, and feel sensations that 

seem real but do not exist. Their 

effects typically begin within 20 to 

90 minutes of ingestion and can last 

as long as 12 hours. Experiences are 

often unpredictable and may vary 

with the amount ingested and the 

user’s personality, mood, expectations, 

and surroundings. The effects of 

hallucinogens like LSD can be 

described as drug-induced psychosis—

distortion or disorganization of a 

person’s capacity to recognize reality, 

think rationally, or communicate with 

others. Users refer to LSD and other 

hallucinogenic experiences as “trips” 

and to acute adverse or unpleasant 

experiences as “bad trips.” On some 

trips, users experience sensations 

that are enjoyable and mentally 

stimulating and that produce a sense 

of heightened understanding. Bad 

trips, however, include terrifying 

thoughts and nightmarish feelings of 

anxiety and despair that include fears 

of losing control, insanity, or death. 

Specific short-term effects of LSD and 

psilocybin include:

LSD

•	 Increased blood pressure, heart rate, 

and body temperature

•	 Dizziness and sleeplessness

•	 Loss of appetite, dry mouth, 

and sweating 

•	 Numbness, weakness, and tremors 

•	 Impulsiveness and rapid emotional 

shifts that can range from fear to 

euphoria, with transitions so rapid 

that the user may seem to experience 

several emotions simultaneously 

Psilocybin†

•	 Feelings of relaxation (similar to 

effects of low doses of marijuana)

•	 Nervousness, paranoia, and panic 

reactions

•	 Introspective/spiritual experiences

Ingesting hallucinogenic drugs can cause users 

to see images, hear sounds, and feel sensations 

that seem real but do not exist. 

4 NIDA Research Report Series
What are the LongTerm Effects of 

Hallucinogens? 

LSD users quickly develop a high 

degree of tolerance to the drug’s 

effects, such that repeated use requires 

increasingly larger doses to produce 

similar effects. Use of hallucinogenic 

drugs also produces tolerance to 

other drugs in this class, including 

psilocybin and mescaline.‡ Use 

of classic hallucinogens does not, 

however, produce tolerance to drugs 

that do not act directly on the same 

brain cell receptors (in other words, 

there is no cross-tolerance to drugs that 

act on other neurotransmitter systems, 

such as marijuana, amphetamines, or 

PCP, among others). Furthermore, 

tolerance for hallucinogenic drugs is 

short-lived—it is lost if the user stops 

taking the drugs for several days—and 

physical withdrawal symptoms are 

typically not experienced by users when 

chronic use is stopped. 

Two long-term effects—persistent 

psychosis and hallucinogen persisting 

perception disorder (HPPD; also 

often referred to as “flashbacks”)—

have been associated with use of 

classic hallucinogens (see sidebar). 

Although occurrence of either is 

rare, it is also unpredictable and may 

happen more often than previously 

thought, and sometimes both 

conditions occur together. While 

the exact causes are not known, 

both conditions are more often 

seen in individuals with a history 

of psychological problems but can 

happen to anyone, even after a single 

exposure. There is no established 

treatment for HPPD, in which 

flashbacks may occur spontaneously 

and repeatedly although less intensely 

than their initial occurrence. Some 

antidepressant and antipsychotic 

drugs can be prescribed to help 

improve mood and treat psychoses, 

however. Psychotherapy may also 

help patients cope with fear or 

confusion associated with visual 

disturbances or other consequences 

of long-term LSD use. More research 

on the causes, incidence, and longterm effects of both disorders is being 

conducted.

Long-Term Effects 

of Hallucinogens

Persistent psychosis

• Visual disturbances

• Disorganized thinking

• Paranoia

• Mood disturbances

Hallucinogen Persisting 

Perception Disorder (HPPD)

• Hallucinations

• Other visual disturbances 

(such as seeing halos or trails 

attached to moving objects)

• Symptoms sometimes 

mistaken for neurological 

disorders (such as stroke or 

brain tumor)

What are the Effects of Common Dissociative Drugs 

on the Brain and Body?

How Do Dissociative Drugs Work?

Laboratory studies suggest that dissociative drugs, including PCP, ketamine, and DXM, 

cause their effects by disrupting the actions of the brain chemical glutamate at certain 

types of receptors—called N-methyl-D-aspartate (NMDA) receptors—on nerve cells 

throughout the brain.10,11 Glutamate plays a major role in cognition (including learning and 

memory), emotion, and the perception of pain (the latter via activation of pain-regulating 

cells outside of the brain). PCP also alters the actions of dopamine, a neurotransmitter 

responsible for the euphoria and “rush” associated with many abused drugs. 

Salvia divinorum works differently. While classified as a dissociative drug, salvia causes its effects by activating a specific 

type of opioid receptor (the kappa opioid receptor) on nerve cells.12,13 These receptors differ from those activated by the more 

commonly known opioids such as heroin and morphine.

LSD users quickly develop a high degree of tolerance 

to the drug’s effects, such that repeated use requires 

increasingly larger doses to produce similar effects. 

‡ Mescaline is not described in this report.

NIDA Research Report Series 5
What are the Long-Term Effects of 

Dissociative Drugs?

While the long-term use of most dissociative drugs has not been investigated 

systematically, research shows that repeated use of PCP can lead to tolerance 

and the development of a substance use disorder that includes a withdrawal 

syndrome (including craving for the drug, headaches, and sweating) when drug 

use is stopped. Other effects of long-term PCP use include persistent speech 

difficulties, memory loss, depression, suicidal thoughts, anxiety, and social 

withdrawal that may persist for a year or more after chronic use stops.

What are the Short-Term Effects of Dissociative Drugs?

Dissociative drugs can produce visual and auditory distortions and a sense of floating and dissociation (feeling 

detached from reality) in users. Use of dissociative drugs can also cause a user to experience anxiety, memory loss, 

and impaired motor function, including body tremors and numbness. These effects, which depend on the amount of 

the drug taken, are also unpredictable—typically beginning within minutes of ingestion and lasting for several hours 

(although some users report feeling the drug’s effects for days). See text box for general effects of dissociative drugs.

General Common Effects of Dissociative Drugs

Low to Moderate Doses High Doses

Numbness Hallucinations

Loss of coordination, disorientation, and confusion

Dizziness, nausea, vomiting

Changes in sensory perceptions (such as 

sight, sound, shapes, time, and body image)

Hallucinations

Feelings of detachment from self and environment

Increase in blood pressure, heart rate, respiration, 

and body temperature

Memory loss

Physical distress, including dangerous changes in blood 

pressure, heart rate, respiration, and body temperature

Marked psychological distress, including feelings of extreme 

panic, fear, anxiety, paranoia, invulnerability, exaggerated 

strength, and aggression

Use with high doses of alcohol or other central nervous 

system depressants can lead to respiratory distress or 

arrest, resulting in death

In addition to these general 

effects, different dissociative 

drugs can produce a variety of 

distinct and dangerous effects. 

For example, at moderate to high 

doses, PCP can cause a user to 

have seizures or severe muscle 

contractions, become aggressive 

or violent, or even experience 

psychotic symptoms similar to 

schizophrenia. At moderate to high 

doses, ketamine can cause sedation, 

immobility, and amnesia. At high 

doses, ketamine users also report 

experiencing terrifying feelings of 

almost complete sensory detachment 

likened to a near-death experience 

(called a “K-hole,” similar to a 

bad LSD trip). Salvia users report 

intense but short-lived (up to 30 

minutes) effects, including emotional 

mood swings (ranging from sadness 

to uncontrolled laughter). 

DXM, which is safe and 

effective as a cough suppressant 

and expectorant when used at 

recommended doses (typically 15–30 

milligrams), can lead to serious side 

effects when abused. For example, 

use of DXM at doses from 200 

to 1,500 milligrams can produce 

dissociative effects similar to PCP 

and ketamine and increase the risk 

of serious central nervous system 

and cardiovascular effects such as 

respiratory distress, seizures, and 

tachycardia (increased heart rate) 

from the antihistamines found in 

cough medicines.

6 NIDA Research Report Series
Glossary

Central Nervous System: The brain and spinal cord.

Cerebral cortex: The region of the brain responsible 

for cognitive functions including reasoning, mood, 

and perception of stimuli. 

Dissociative: a type of compound, such as 

phencyclidine or ketamine, that produces an 

anesthetic effect characterized by a feeling of being 

detached from the physical self. 

DXM: A common street name for dextromethorphan. 

Flashback: A sudden but temporary recurrence 

of aspects of a drug experience (including sights, 

sounds, and feelings) that may occur days, weeks, or 

even more than a year after hallucinogenic drug use. 

Glutamate: An excitatory neurotransmitter found 

throughout the brain that influences the reward 

system and is involved in learning and memory, 

among other functions.

Hallucinogen: A drug that produces hallucinations—

distortions in perception of sights and sounds—and 

disturbances in emotion, judgment, and memory. 

HPPD: Hallucinogen persisting perception disorder; 

the spontaneous and sometimes continuous 

recurrence of perceptual effects of LSD long after an 

individual has ingested the drug. 

Kappa opioid receptor: A receptor on nerve cells 

that is activated by certain opioid-like compounds 

produced in the body. These receptors differ from 

those activated by the more commonly known 

opioids, such as heroin and morphine.

Neurotransmitter: A chemical compound that acts as 

a messenger to carry signals from one nerve cell to 

another. 

NMDA receptors: N-methyl-D-aspartate receptors, 

a type of glutamate receptor that is important for 

learning and memory; it is the target of drugs such 

as PCP and ketamine. 

Persistent psychosis: Unpredictable and long-lasting 

visual disturbances, dramatic mood swings, and 

hallucinations experienced by some LSD users after 

they have discontinued use of the drug. 

Serotonin: A neurotransmitter involved in a broad 

range of effects on perception, movement, and 

emotions. Serotonin and its receptors are the targets 

of most hallucinogens.

1. Substance Abuse and Mental Health 

Services Administration. Results 

from the 2012 National Survey on 

Drug Use and Health: Summary of 

National Findings, NSDUH Series H-44, 

HHS Publication No. (SMA) 12-4713. 

Rockville, MD: U.S. Department of 

Health and Human Services, Substance 

Abuse and Mental Health Services 

Administration, 2012. 

2. Johnston, L.D.; O’Malley, P.M.; 

Bachman, J.G.; and Schulenberg, J.E. 

Monitoring the Future national results 

on adolescent drug use: Overview of 

key findings, 2013. Ann Arbor: Institute 

for Social Research, the University of 

Michigan, 2014.

3. Hibell, B.; Guttormsson, U.; Ahlström, 

S.; Balakireva, O.; Bjarnason, T.; 

Kokkevi, A.; and Kraus, L. The 2011 

ESPAD Report: Substance Use Among 

Students in 36 European Countries.

Stockholm, Sweden: The Swedish 

Council for Information on Alcohol and 

Other Drugs (CAN), 2012.

4. Bogenschutz, M.P.; and Pommy, J.M. 

Therapeutic mechanisms of classic 

hallucinogens in the treatment of 

addictions: From indirect evidence to 

testable hypotheses. Drug Test Anal

4(7–8): 543–555, 2012.

5. Bonson, K.R. Hallucinogenic Drugs. In 

Encyclopedia of Life Sciences, Nature 

Publishing Group, 2001.

6. Passie, T.; Halpern, J.H.; Stichtenoth, 

D.O.; Emrich, H.M.; and Hintzen, A. 

The pharmacology of lysergic acid 

diethylamide: A review. CNS Neurosci 

Ther 14(4): 295–314, 2008.

7. Nichols, D.E. Hallucinogens. Pharmacol 

Ther 101(2): 131–181, 2004.

8. Schindler, E.A.; Dave, K.D.; Smolock, 

E.M.; Aloyo, V.J.; and Harvey, J.A. 

Serotonergic and dopaminergic 

distinctions in the behavioral 

pharmacology of (+/-)-1-(2,5-dimethoxy4-iodophenyl)-2-aminopropane (DOI) 

and lysergic acid diethylamide (LSD). 

Pharmacol Biochem Behav 101(1): 

69–76, 2012.

9. Lee, H.M.; and Roth, B.L. 

Hallucinogen actions on human brain 

revealed. Proc Natl Acad Sci U S A

109(6): 1820–1821, 2012.

10. Morgan, C.J.; Curran, H.V.; and 

Independent Scientific Committee 

on Drugs. Ketamine use: A review. 

Addiction 107(1): 27–38, 2012.

11. Morris, B.J.; Cochran, S.M.; and Pratt, 

J.A. PCP: From pharmacology to 

modelling schizophrenia. Curr Opin 

Pharmaco 5(1):101–106, 2005.

12. Cunningham, C.W.; Rothman, 

R.B.; and Prisinzano, T.E. 

Neuropharmacology of the naturally 

occurring kappa-opioid hallucinogen 

salvinorin A. Pharmacol Rev 63(2): 

316–347, 2011.

13. MacLean, K.A.; Johnson, M.W; 

Reissig, C.J.; Prisinzano, T.E.; and 

Griffiths, R.R. Dose-related effects of 

salvinorin A in humans: Dissociative, 

hallucinogenic, and memory effects. 

Psychopharmacology (Berl). 226(2): 

381–392, 2013.

 References

NIDA Research Report Series 7
NIH Publication Number 14-4209 • Revised January 2014

Feel free to reprint this publication.

To learn more about hallucinogens

and other drugs of abuse, 

visit the NIDA Web site at 

www.drugabuse.gov or 

contact the DrugPubs Research 

Dissemination Center at 

877-NIDA-NIH (877-643-2644; 

TTY/TDD: 240-645-0228). 

Where can I get further information about hallucinogens?

What’s on the NIDA Web Site

• Information on drugs of abuse and 

related health consequences

• NIDA publications, news, and 

events

• Resources for health care 

professionals

• Funding information (including 

program announcements and 

deadlines) 

• International activities 

• Links to related Web sites (access 

to Web sites of many other 

organizations in the field)

NIDA Web Sites

www.drugabuse.gov 

www.teens.drugabuse.gov

www.drugabuse.gov/publications/

term/160/DrugFacts

www.easyread.drugabuse.gov

For Physician Information

www.drugabuse.gov/nidamed

Other Web Sites

Information on hallucinogens and 

dissociative drugs is also available 

through these other Web sites:

• Substance Abuse and Mental 

Health Services Administration 

Health Information Network: 

www.samhsa.gov

• Drug Enforcement Administration: 

www.deadiversion.usdoj.gov 

• Monitoring the Future: 

www.monitoringthefuture.org/ 

• The Partnership at Drug Free.org: 

www.drugfree.org/drug-guide

8 NIDA Research Report Series