Hallucinogen use has a rich history across the world, and many people have used these substances to achieve mystical experiences. Recreational use of hallucinogens is popular in the United States, and researchers are looking to discover how these psychedelic compounds work and how they may be used in medicine.

The family of drugs known as hallucinogens is large, and these substances work in unique ways and produce a variety of side effects. Broadly speaking, there are two categories of hallucinogens:

Two Types of Hallucinogens

  • Classical Hallucinogens

    This category is what typically comes to mind when people think of hallucinogenic drugs. Commonly known as “psychedelics,” classical hallucinogens include LSD, mescaline, DMT and psilocybin (magic mushrooms). Classical hallucinogens have substantial mind-altering properties but are not associated with serious risks for misuse or addiction. However, they are classified as Schedule I drugs by the U.S. Drug Enforcement Administration. When someone stops taking classical hallucinogens, they are not likely to experience withdrawal symptoms. With regular use, however, it’s possible to develop a tolerance. This means that a person requires larger doses in order to achieve the same effects.

  • Dissociative Hallucinogens

    This category includes drugs like ketamine, PCP, dextromethorphan, and nitrous oxide. Dissociative hallucinogens are more frequently associated with risks for dependence and addiction than classical hallucinogens. As a result, they are more likely to cause withdrawal symptoms when someone quits taking them.

Although some people consider MDMA to be a hallucinogen, it is not. Hallucinogens are drugs that are taken specifically for their hallucinogenic properties. MDMA is known as an “empathogen” that increases sensory perception, empathy, and social connection. It is not always linked to hallucinations, but it may cause them as a secondary effect.

The mental effects of hallucinogens are frequently positive, but negative effects are not uncommon. Frequently reported side effects of classical and dissociative hallucinogens include:

In addition, dissociative hallucinogens can cause someone to experience detachment or dissociation from reality.

Hallucinogen Withdrawal Symptoms

The difference between detox and withdrawal is important to understand in the context of hallucinogens:

  • Detox refers to the metabolic process of eliminating a drug from the body. Detox may or may not be associated with symptoms of withdrawal.
  • Withdrawal is the result of chemical dependence. Dependence describes a physical need for the presence of a drug, which makes people continue to use the drug over time. For drugs that are associated with dependence and addiction, withdrawal symptoms generally begin during the detox period.

Both classical and dissociative hallucinogens are associated with a detox period after someone takes them. Someone who is “coming down” off of a hallucinogenic drug may experience discomfort, fatigue or restlessness in the hours following the “trip.” These are not symptoms of withdrawal and typically do not require professional supervision or assistance.

People who use classical hallucinogens do not experience withdrawal symptoms when they stop taking the drugs. Dissociative hallucinogens, however, may be associated with withdrawal symptoms.

In particular, phencyclidine (PCP) is associated with withdrawal symptoms. Other dissociative hallucinogens may also have withdrawal symptoms, including:

  • Hallucinogen Withdrawal Symptoms




    Lose of pleasure

    Sense of unease or dissatisfaction

    Drug craving


    Lack of motivation

The so-called “acid flashback” is related to hallucinogen persisting perception disorder (HPPD). HPPD is a rare and poorly understood consequence of hallucinogen use, and its symptoms include perceptual disturbances that are similar to a hallucinogenic trip. This is not believed to be caused by hallucinogen use in itself. Rather, evidence suggests that HPPD is related to the presence of pre-existing mental health conditions.

How Long Do Hallucinogens Stay in Your System?

The amount of time that a drug is detectable in your system depends on the drug’s half-life. A half-life is the amount of time required for the body to metabolize half of the drug. For example, if there are 10 units of a drug in a person’s system, the first half-life will metabolize 5 units. The second half-life will metabolize half of the 5 remaining units, leaving 2.5 units in the system. This continues until all of the drug is gone.

Generally, a drug will be completely metabolized within 5 half-lives. For a drug with a half-life of 1 day, it may be detectable in the system for 5 days after it was last used.

Most countries do not allow research on the effects of classical hallucinogens in humans. As a result, half-lives are often determined using animal studies, many of which are decades old. Precise half-lives for many hallucinogenic substances in humans remain unclear.

Typical half-lives and windows of detection for common hallucinogens are as follows:

  • LSD: 3 hours (detectable for approximately 15 hours)
  • Mescaline: 6 hours (detectable for approximately 30 hours)
  • Ayahuasca: 1 hour (detectable for approximately 5 hours)
  • PCP: 3 days (detectable for approximately 15 days)
  • Ketamine: 45 minutes (detectable for approximately 3.75 hours)
  • Dextromethorphan (DXM): 3 to 6 hours (detectable for approximately 15 to 30 hours)

As drugs are metabolized, they are broken into byproducts that often have different half-lives. If a drug test looks for a metabolic byproduct rather than the drug itself, the window of detection may be very different.

Hallucinogen Withdrawal Timeline

Classical hallucinogens are not associated with withdrawal symptoms. Someone may feel fatigued or restless in the hours following the “trip,” but these are not withdrawal symptoms. Many people who take classical hallucinogens report long-lasting positive effects after their hallucinogenic experience.

Different types of dissociative hallucinogens will have slightly different withdrawal timelines. In general, the signs and symptoms of withdrawal will resolve within a few days after the last use. In extreme cases, symptoms like depression and loss of pleasure may persist for 7 to 10 days.

Factors Affecting Hallucinogen Withdrawal

The withdrawal timeline for dissociative hallucinogens depends on a number of factors, including:

  • Hallucinogen Withdrawal Factors

    Degree of dependence

    Duration of use

    Frequency of use

    Dose taken

    Route of administration





    Overall physical and mental health

Hallucinogen Detox

People with a dependence on dissociative hallucinogens may face an uncomfortable detox period that can last for hours or even days. There are several rehab options that can accommodate people who are experiencing different degrees of withdrawal:

Medically supervised detox includes around-the-clock care and supervision by medical professionals and addiction specialists. When assessing medical detox centers, it is important to confirm that the staff has experience in supporting people who are detoxing from dissociative hallucinogens.

Hallucinogen detox rarely requires medication-assisted detox. In extreme cases, drugs may be prescribed that can reduce symptom severity. There are many drug detox centers in Florida, but they can differ in the quality of services and care. Look for one with experienced addiction specialists who can prescribe medications if necessary.

Outpatient detox comes in several forms, ranging from intensive all-day programs to weekly therapy sessions. To determine whether an outpatient program is appropriate, consult with a facility that has experience in outpatient treatment for hallucinogen use.

People who have mild dependence and are motivated to quit may be able to successfully detox from drugs at home. It can be helpful to enlist the support of a trusted friend or loved one ahead of time. It is also important to stay hydrated and maintain a healthy diet while detoxing.

Finding a Detox Center

There are many detox centers, but they are not all alike. When you are evaluating rehab programs, look for the following:

  • Factors to Look for in a Detox Center

    Staff that is experienced with hallucinogen detox

    Medical professionals who can prescribe drugs or intervene in the case of complications

    Multidisciplinary teams that can address questions and concerns as they arise

    Programs that include care for every step of recovery, from detox to aftercare

    Evidence-based treatment programs that include traditional and cognitive behavioral therapy sessions

    Ability to provide a dual diagnosis

Our Drug Detox Center

The Recovery Village Palm Beach at Baptist Health

4905 Lantana Rd
Lake Worth, FL 33463


Key Points: Hallucinogens Withdrawal and Detox

Some key points to keep in mind about hallucinogen withdrawal and detox include:

  • While classical hallucinogens like LSD are not associated with addiction or withdrawal, dissociative hallucinogens like ketamine and PCP are
  • Symptoms of withdrawal include depression, loss of pleasure, irritability, and anxiety
  • There are several types of detox programs that are designed to support people from many different backgrounds
  • When you are looking for a detox center, do your homework and find the one that is most appropriate for you

If you or someone you love is struggling with hallucinogen use, The Recovery Village Palm Beach at Baptist Health can help. Contact us today to learn how our addiction specialists can tailor a detox and recovery program that works well for your needs.

Medical Disclaimer: The Recovery Village aims to improve the quality of life for people struggling with a substance use or mental health disorder with fact-based content about the nature of behavioral health conditions, treatment options, and their related outcomes. We publish material that is researched, cited, edited and reviewed by licensed medical professionals. The information we provide is not intended to be a substitute for professional medical advice, diagnosis or treatment. It should not be used in place of the advice of your physician or other qualified healthcare provider.