Q&A: Long-Term Physical Effects

Currently, the long-term effects of psychedelics are poorly understood. It’s quite rare for people to become addicted to most psychedelics, but using these substances does affect the body. Symptoms can range from fatigue and grogginess to reports of recurring perceptual changes that can last for days, and sometimes weeks or years, after the experience. 

Brian Anderson

Brian Anderson

Brian Anderson is a psychiatrist, assistant professor, and researcher at the University of California, San Francisco. He is an investigator with BCSP. For over a decade, he has conducted both ethnographic and clinical research related to psychoactive drug use, including studying ayahuasca-using religious groups in South America and psilocybin therapy for people with serious medical illnesses.


BCSP

Do psychedelics cause hangovers?

Brian Anderson

“There are reports of people feeling hungover, fatigued, or a little foggy the day or a couple of days after taking some psychedelics. There is also a real difference between stimulant-based psychedelics, like MDMA, that have psychedelic effects, versus the classic psychedelics like psilocybin and ayahuasca. MDMA-like drugs can lead to side effects such as feeling hungover in different ways. But certainly, people can feel tired and foggy-headed with a number of different psychedelics. 

In psilocybin research, one of the most common side effects that people report in the days after treatment is fatigue. They report that even after taking psilocybin during the daytime (meaning they are not staying up all night because they took the drug late in the evening). Headaches can also be a lingering side effect after psilocybin.”


BCSP

Can MDMA withdrawal cause fatigue and depression?

Brian Anderson

“When people use drugs that they call ‘MDMA’ in community settings, there are often other substances mixed in with them, both potential impurities and other drugs. They may be having some of these adverse effects from the other substances. 

It’s also important to emphasize that whenever a substance is used in a way that changes someone’s sleep-wake cycle—for instance, if someone takes a psychedelic drug like MDMA and stays up all night—then feeling fatigued, hungover, or like they’re ‘coming down’ in an uncomfortable way over the next few days may in large part be due to losing a night of sleep. That’s one reason why, when these substances are used in clinical trials in a therapeutic setting, it’s often done during the day. We try to make sure people have time to sleep and recover afterward.

Also, it’s worth mentioning that one participant in the recent Phase 3 trial of MDMA-assisted psychotherapy for PTSD (published in Nature Medicine) did withdraw from the study in part because they experienced depressed mood following an MDMA treatment session. But there isn’t conclusive evidence that the ingestion of pure MDMA in clinical settings leads to blue Mondays in users.”

“It’s not just about taking a substance. The work that unfolds between sessions is thought to be really important in terms of how a substance may actually help people.”


BCSP

What is Hallucinogen Persisting Perception Disorder?

Brian Anderson

“Hallucinogen Persisting Perception Disorder, or HPPD, is when people experience perceptual distortions long after using a drug, like a psychedelic. People report seeing ‘trailers’—meaning if they move their hand in front of their face, it’s almost like they can see afterimages of their hands slowly moving across their visual field or colored lights or shapes out of the corner of their eye. 

It’s not just about seeing things afterward, even though that’s probably the most common problem. People also seek clinical care after using psychedelics and other drugs for auditory or somatic sensations that are unusual, distressing, and impairing.

Unfortunately, there aren’t great treatments for it.
The prevalence of HPPD is still unclear. One large survey of psychedelic users found that 4.2 percent experienced distressing persisting visual experiences after psychedelic use.”


BCSP

Do people need to eat special foods, vitamins, or supplements before or after taking a psychedelic substance?

Brian Anderson

“There are different opinions on the proper ways to prepare for, recover from, and make the most use of psychedelic experiences. You’ll find a number of different opinions out there on special foods or diets, or the use of supplements, vitamins, and herbs. I don’t know if there is a solid, reliable body of evidence that many people would agree upon. 

But with ayahuasca, and some other psychedelics like 5-MeO-DMT, the idea of combining those drugs with certain other compounds is thought to be dangerous. Specifically, combining different psychedelics with compounds that are monoamine oxidase inhibitors (MAOIs) has led to people having very strong, overwhelming psychological reactions to the psychedelics.

Sometimes this contributes to severe medical outcomes or even death. There’s been a number of cases where people will combine ayahuasca or ayahuasca-like substances that have MAOIs in them with smoking 5-MeO-DMT or related compounds in non-clinical settings, and there have been fatalities. Whether it is safe to combine different psychedelics needs more careful study.”


BCSP

After a trip, do users need to wait a significant amount of time to take psychedelics or other drugs again?

Brian Anderson

“If someone takes a psychedelic drug like LSD or psilocybin every day, the drug will quickly lose its psychoactive effects because of tolerance. There are always risks when someone takes a psychedelic, so safety is an important consideration here. The optimal interval between uses of a psychedelic depends on why someone is taking the drug in the first place. It’s worth asking, ‘What good is it doing for people?’ If they’re approaching it to give them insights for well-being or personal enhancement, how much psychological work can you really get done if you wait only a week between dosing sessions? There are teachings out there about spacing out the use of the substance and trying to optimize the work and growth you do in between.

It’s not just about taking a substance. The work that unfolds between sessions is thought to be really important in terms of how a substance may actually help people.”

This interview was edited for length and clarity.

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