Hallucinogens are a family of drugs, from LSD and psilocybin to PCP and ketamine, that alter how a person perceives time, space and their own body, and effects can last from under an hour to most of a day. Physical signs show up first, but the bigger dangers are what happens during a bad trip and which combinations turn it into an emergency. Only some of these drugs carry a real risk of addiction, and where a use disorder develops, counseling is the core of treatment.
Key Points About Hallucinogens
- Dilated pupils, a faster heartbeat and higher blood pressure are the common physical signs, often with nausea.
- Hallucinogens split into psychedelics such as LSD, dissociatives such as PCP and ketamine, and the less common deliriants.
- Effects last from about 20 minutes for smoked DMT to 12 hours or more for LSD.
- In 2025, about 495,000 people had a use disorder, which PCP and ketamine can cause but LSD usually does not.
- Bad trips, injuries while high, dangerous drug mixes and, rarely, lasting visual changes are the main risks.
- Treatment centers on counseling, since no medication is approved for the disorder, and LSD, psilocybin and DMT remain illegal federally.
Signs Someone Is on a Hallucinogen: Symptoms and Effects
Wider pupils, a quicker pulse and higher blood pressure top the list. Nausea, hallucinations and a distorted sense of time and place follow. Swallowed, effects begin within 20 to 90 minutes; smoked or snorted, within minutes.
Effects by Type of Hallucinogen
Psychedelics such as LSD, psilocybin, mescaline (peyote) and DMT raise body temperature, heart rate and blood pressure, with nausea, panic or paranoia and, rarely, psychosis. Dissociatives such as PCP, ketamine and DXM (dextromethorphan, in cough medicine) numb the body and blur memory, with anxiety, fear and paranoia, and they shift heart rate and blood pressure; PCP can bring on agitation, violence, high body temperature and seizures. Deliriants, from high doses of diphenhydramine, jimsonweed or scopolamine, bring delirium and hallucinations. MDMA (ecstasy or molly) is often grouped with hallucinogens but acts differently; see MDMA and ecstasy.
How Long Do Hallucinogens Last?
Duration depends on the drug and the dose: smoked salvia is over in under half an hour, while LSD may run 12 hours or more.
| Drug | Effects start | Effects last |
|---|---|---|
| LSD | 30-60 minutes | Up to 12 hours, sometimes longer |
| Psilocybin (magic mushrooms) | 20-40 minutes | 4-6 hours |
| Mescaline (peyote) | 30-90 minutes | About 12 hours |
| DMT (smoked) | Within minutes | 20-60 minutes |
| PCP | Within minutes | Several hours, sometimes up to 48 hours |
| Ketamine and DXM | Within minutes | Several hours |
| Salvia | Within a minute | Usually under 30 minutes |
Flashbacks, brief returns of visual effects, usually come within a week and are short.
Types of Hallucinogens
Hallucinogens fall into three groups by how they act on the brain. The psychedelics, which include LSD and psilocybin, work mainly on serotonin receptors. PCP and ketamine are dissociatives, and they block a receptor called NMDA. Deliriants are the third and least common group.
| Type | Examples | How they affect the brain | Addiction potential | Main danger |
|---|---|---|---|---|
| Psychedelics | LSD, psilocybin, mescaline (peyote), DMT, ayahuasca, and others on the list of psychedelic drugs | Act mainly on serotonin (5-HT2A) receptors | Addiction does not typically follow LSD, psilocybin or mescaline use, and tolerance climbs fast; DMT has little research behind it | Bad trips, risky behavior, rare lasting effects |
| Dissociatives | PCP, ketamine and DXM (cough medicine taken at high doses) | Block NMDA receptors | A use disorder can develop with PCP or ketamine | Agitation, injuries, seizures (PCP); bladder damage (ketamine) |
| Deliriants | High doses of diphenhydramine, jimsonweed (datura), scopolamine | Block acetylcholine | Rarely reported | Delirium, high body temperature, fast heart rate |
Salvia acts on kappa opioid receptors, not serotonin or NMDA, so it fits none of the three groups.
Related articleList of Psychedelic DrugsPsychedelic drugs are powerful substances intended to make people experience altered consciousness and perception. These drugs can cause serious harm to the user.
Risks of Hallucinogens: Bad Trips, Injuries and Lasting Effects
Most of the risk arrives while someone is high: a bad trip of panic and fear, judgment loose enough to cause injury, and unpredictable reactions when a hallucinogen meets alcohol or lithium. Flashbacks can return a trip’s visual effects briefly; hallucinogen persisting perception disorder (HPPD) is rarer and keeps them coming back for months or years, with no established treatment.
In 2025, the Substance Abuse and Mental Health Services Administration (SAMHSA) reported 9.1 million people aged 12 and older using hallucinogens, 6.5 million using psilocybin, and 495,000 with a hallucinogen use disorder. Among 18- to 25-year-olds, 2.2 million used them, or 6.0% of that age group.
9.1M
Past-year hallucinogen use, age 12 and older (SAMHSA, 2025)
6.5M
Past-year psilocybin use, age 12 and older (SAMHSA, 2025)
2.2M
Young adults 18 to 25 who used hallucinogens, or 6.0% (SAMHSA, 2025)
495K
Hallucinogen use disorder, age 12 and older (SAMHSA, 2025)
Bad trips
Injuries
Psychosis
Flashbacks and HPPD
Seizures
Teens
Heavy ketamine use can also damage the bladder.
Bad Trips and Emergency Signs: When to Call 911
Call 911 for a seizure, trouble breathing, very high body temperature, severe agitation or violence, or someone who cannot be woken after a hallucinogen. Without those signs, a bad trip is rarely an emergency: stay with them somewhere calm and quiet, and call Poison Control at 1-800-222-1222 for advice.
Seizure
Trouble breathing
Very high body temperature
Severe agitation or violence
Cannot be woken
Chest pain or a racing heart
How to Help Someone Having a Bad Trip
- Stay beside them and keep your voice calm. Remind them the drug is causing this and it will pass.
- Move them to a quiet, dim room.
- Do not give them alcohol or any other drug.
- Keep pills or packaging to show emergency staff.
- If someone talks about hurting themselves, they can call or text 988, and call 911 if they are in danger.
Dangerous Combinations
Some mixtures turn a difficult trip into a medical emergency.
| Combination | Why it is risky |
|---|---|
| Psychedelics with lithium | An analysis in Pharmacopsychiatry found seizures in 47% of 62 online reports (self-reported data, 2021) |
| Ayahuasca with SSRIs (selective serotonin reuptake inhibitors) or other antidepressants | A risk of serotonin syndrome, which may become life-threatening |
| Hallucinogens with alcohol or other drugs | The risk of poor decisions, accidents and unpredictable effects rises |
Are Hallucinogens Addictive? Signs of Hallucinogen Use Disorder
Most hallucinogens are not considered highly addictive. PCP and ketamine can cause a use disorder.
| Drug | What research shows |
|---|---|
| LSD and psilocybin | Do not usually lead to addiction; tolerance builds fast but eases within days of stopping |
| DMT | Not well studied. It does not appear to cause tolerance |
| PCP | A use disorder can follow repeated use; people report cravings, headaches and sweating once they stop |
| Ketamine | Outside a medical setting, it can bring cravings and withdrawal symptoms |
How Hallucinogen Use Disorder Is Diagnosed
A clinician counts at least 2 of the 10 listed signs inside a 12-month period. Mild is 2 or 3 signs, moderate 4 or 5, and severe 6 or more. Withdrawal is not among them, since no withdrawal syndrome has been established for these drugs.
Losing control
Life problems
Risky use
Tolerance
Someone with a hallucinogen use disorder may draw away from close friends and family, give more time to others who use, drop interests that once mattered, let work or school slip, or hit legal and financial trouble.
Microdosing: What the Research Shows
Microdosing means taking a psychedelic in a dose far below the amount that produces a full trip, somewhere around a tenth to a twentieth of one, often in the hope of lifting mood or sharpening focus. Research has not yet shown the practice to be safe or effective, and the trials that tested it against a placebo found no advantage over the placebo.
Placebo kept pace
No relief for mood
Legal risk, unknown dose
Neither study rules out every possible use of a microdose, but neither found an effect that a placebo did not also produce.
Psychedelic Therapy and the Law in 2026
No psychedelic has FDA approval apart from esketamine, a form of ketamine approved for depression and offered only through a certified clinic with monitoring. MDMA-assisted therapy for PTSD was turned down in 2024, and its resubmitted application has no decision yet. A depression treatment built on psilocybin is still under review. Federal law keeps psilocybin, LSD, MDMA and DMT on Schedule I, though a handful of states now permit supervised psilocybin use in licensed programs.
| Area | Status |
|---|---|
| MDMA-assisted therapy for PTSD | In June 2024, advisers opposed it, voting 2 to 9 on effectiveness and 1 to 10 on benefits versus risks. The FDA declined approval in August 2024, and a resubmitted application was reported in August 2026, with no decision yet |
| Psilocybin for treatment-resistant depression | Has FDA breakthrough status, along with a Commissioner’s National Priority Voucher and a rolling review. Compass Pathways looks to complete its application in late 2026, with no approval granted yet |
| Esketamine (Spravato) | A form of ketamine that the FDA approved for hard-to-treat depression, dispensed only at a certified clinic with monitoring |
| Federal action | An executive order in April 2026 calls for quicker study and review of psychedelic treatments, and in July 2026 the FDA released final guidance covering psychedelic clinical trials |
| Oregon | Licensed psilocybin service centers served 5,935 people in 2025, the Oregon Health Authority reports |
| Colorado | Adults 21+ may use psilocybin mushrooms personally, with no retail sales, and 47 healing centers were licensed as of October 2026, according to the state’s Natural Medicine Division |
| New Mexico | Its medical psilocybin program covers PTSD and treatment-resistant depression among other conditions, with treatment expected to reach the first patients near the end of 2026 |
| Texas and New Jersey | Texas has set aside $50 million for ibogaine clinical trials starting in 2025, and New Jersey launched a psilocybin therapy pilot worth $6 million at three hospitals in 2026 |
A session inside a trial or a licensed center, with screening beforehand and trained staff present, is not the same as using these drugs alone. The Oregon Health Authority counted 13 calls to emergency services during psilocybin sessions in 2025, even though screening was in place.
Treatment for Hallucinogen Use Disorder
Counseling is the core of treatment. A person with a hallucinogen use disorder works with a therapist, and cognitive behavioral therapy is one of the approaches used. Care reaches co-occurring conditions, since anxiety, depression and psychosis can accompany or follow hallucinogen use. No medication is approved to treat the disorder itself; doctors prescribe for those conditions when they appear, so medication sits alongside counseling rather than replacing it.
| Treatment option | What it involves |
|---|---|
| Cognitive behavioral therapy | Spotting the situations that lead to use, and building coping skills |
| Other behavioral therapies | Motivational and family approaches, matched to what the person is ready for |
| Outpatient and inpatient rehab | Most people do well with outpatient care; inpatient care suits severe use, psychosis or a home that is not safe |
| Mental health care | Treatment for anxiety, depression, psychosis or HPPD, which can come with hallucinogen use or follow it |
| Support groups | Peer support during treatment and after it ends |
For PCP specifically, see treatment for PCP addiction. To check what a plan covers, see how to pay for rehab.
How to Help Someone Who Uses Hallucinogens
Pick a calm, private moment and describe what you have noticed, in specifics rather than labels. If they are open to help, offer to look for an assessment or a treatment program together, and make room for support of your own.
Find a quiet moment
Say what you have seen
Suggest an assessment
Talk through the options
Get support for yourself
If they turn help down, a guided intervention is one route to consider. Nothing about helping a loved one with addiction ends with one conversation, and the offer can stay open for months.
Frequently Asked Questions About Hallucinogens
What are the signs someone is on a hallucinogen?
The body usually shows it first. Pupils widen, the heart speeds up and blood pressure rises. What the person reports counts too: they may see or hear things that are not there, lose track of how much time has passed, or seem detached and confused.
Are hallucinogens addictive?
Addiction is not the usual outcome for most of them. LSD and psilocybin rarely lead to a use disorder, while PCP and ketamine carry more risk, and any drug in this group can be misused.
How long do hallucinogens last?
Duration varies by drug. Smoked DMT is over in under an hour. Psilocybin runs 4 to 6 hours. LSD can last 12 hours or more.
What is a bad trip, and what should I do?
A bad trip means panic, paranoia or confusion takes hold while a hallucinogen is working. Stay nearby, somewhere quiet and unhurried, and keep your voice level. Call 911 if there is a seizure, difficulty breathing, a dangerous rise in body temperature or violence. Without those signs, Poison Control at 1-800-222-1222 can advise on what to watch for.
Can hallucinogens cause permanent effects?
Rarely. Hallucinogen persisting perception disorder (HPPD) is the lasting condition to know about: visual changes keep returning long after the drug has cleared, and can go on for months or years. No established treatment exists for HPPD. PCP brings a separate risk, since psychosis from it can run for days to weeks.
Is psilocybin legal?
Not under federal law. Oregon and Colorado run licensed programs where psilocybin can be used under supervision, and New Mexico has a medical program getting under way. The details differ by state: the Oregon Health Authority administers Oregon’s, Colorado licenses its centers through the Natural Medicine Division, and the New Mexico Department of Health runs its own.
Is there medication for hallucinogen addiction?
No. No medication has approval specifically for hallucinogen use disorder. Treatment centers on counseling, and treats any mental health condition alongside it.
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Medical reviewer
Ariella Belote, BSN, RN
Ariella Belote, BSN, RN, has experience working as a nurse in outpatient alcohol and drug addiction treatment, where she worked with clients experiencing various dependencies. She also works to connect clients with local resources designed to support recovery on a daily basis. In addition, she…
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