Bad Trip: The Dark Side of Psychedelics

Psychedelic adverse effects must be balanced against the hope and hype.

Reviewed by Michelle Quirk

Key points

• Some users report fear, depression, and paranoia as well as "existential struggles" and fear of the afterlife.
• Sexual misconduct in the setting of psychedelic-assisted psychotherapy is also a risk.
• A better understanding of adverse events is warranted before psychedelics are approved as medicines.

In my previous two posts, I wrote about the ability of psychedelics to act as “entheogens” that can sometimes lead people to greater belief in God through encounters with divine entities and other profoundly meaningful experiences, while questioning whether such experiences are truly revelatory or merely false beliefs akin to delusions.

In this post, I’ll review recent research confirming that such seemingly positive and transformative experiences are by no means a guarantee and that some can experience a darker side of psychedelic use.

"Bad Trips"

Of course, it has long been known that some people have “bad trips,” including significant psychosis, when using psychedelic drugs. Proponents of the medicinal potential of psychedelics often remind us that the nature of individual experiences is highly influenced by both “set” (what mindset one brings to the experience) and “setting” (the environment and social interaction we have during the experience). And, so, a person with a significant history of trauma shouldn’t be expected to have a cathartic and healing experience just because they ingest a “magic mushroom.” On the contrary, many proponents have argued that psychotherapy is an essential element of psychedelic medicine. Just so, recent clinical trials of psychedelic drugs like MDMA (“ecstasy”) and psilocybin (the active ingredient of psychedelic mushrooms) have involved not just exposure to the drug, but 12 weeks of “psychedelic-assisted psychotherapy.”

Still, in August 2024, the US Food and Drug Administration (FDA) ruled against approving Lykos Therapeutics’ application for MDMA-assisted psychotherapy in the treatment of posttraumatic stress disorder (PTSD) due to concerns about clinical trial methodology as well as inadequate disclosure of adverse events associated with such therapy.

Indeed, in contrast to the hope and hype surrounding psychedelics in recent years, some have been calling for more research on the risks.¹ In 2023, a survey of adverse events documented that some people experience a variety of “extended difficulties” following psychedelic use lasting for more than 3 years including anxiety and fear (in 26 percent of respondents), depersonalization (16 percent), derealization (15 percent), social disconnection (13 percent), depression (12 percent), and paranoia (11 percent).² Instead of having God-encounter experiences leading to feeling a greater connection to God or the Universe, some reported feelings of “spiritual difficulties” (50 percent) and “ontological difficulties” (34 percent) involving the way they understood reality and existence including “existential struggles” (17 percent), delusional beliefs (6 percent), and a sense of hell or an encounter with an evil presence creating a fear of the afterlife (4 percent). One survey respondent described their existential crisis as follows:

I entered the experience believing that my experience is the literal real external world. The experience contained me living out my worst fears, the deepest possible shame. Other experiences so bizarre and dreamlike I could not make sense of them. These memories left a legacy of confusion about what deeper model of reality to use, and repeated experiences of flipping between these models at different times.

Suffice it to say that psychedelic use is by no means always a positive experience. A recent article in The Guardian described a new clinic in Germany specifically designed to help people with negative sequelae of psychedelic use, including hallucination persistent perception disorder (“flashbacks”), depersonalization, derealization, psychosis, and anxiety.³ A variety of similar resources have begun to crop up in recent years including online support groups and hotlines offering help to those who’ve had bad trips.

While a key component of psychedelic-assisted psychotherapy aims to integrate one’s psychedelic experiences—that is, to process and make sense of them in one’s daily life going forward—the inclusion of a psychotherapy component doesn’t guarantee a positive or therapeutic experience either. One of the reasons that the FDA didn’t approve MDMA-assisted psychotherapy back in August was that the Lykos Pharmaceuticals failed to acknowledge ethical violations in their clinical trials that included a headline-making incident involving sexual activity between a study subject and the therapist.⁴ In addition to blowback from the FDA, three scientific papers that had supported the use of MDMA-assisted psychotherapy for PTSD were retracted by the publishing journal as well.⁵

Sexual Misconduct

Unfortunately, another recent survey of adverse experiences during psychedelic use found that sexual misconduct in the setting of psychedelic use is uncommon, but not rare. Among a sample of 1221 respondents, 8 percent reported that either they or someone they know was the victim of inappropriate sexual contact between the users and a “psychedelic sitter, guide, or practitioner.”⁶ To be fair, such rates are on par with sexual misconduct reported during other types of psychotherapy or in clinical encounters with physicians.^7,8 But whether such incidents arise within the “transference” of a therapeutic relationship or the “state of suggestibility and increased vulnerability” that psychedelics can induce,⁶ such vulnerability demands closer scrutiny and the establishment of protections for patients.

Psychedelic psychotherapy may yet turn out to be the revolutionary treatment that many hope it to be for opening ourselves to transformative spiritual awakenings or for the treatment of conditions like major depression or PTSD. But allowing our collective enthusiasm for psychedelic drugs to turn a blind eye to the potential risks of therapy will continue to thwart its success.

Back in 2021, I wrote that “more research is needed to clarify risks and benefits before MDMA-assisted psychotherapy would ever be approved by the FDA.”⁹ Nearly four years later, with several additional research studies since completed, that remains just as true today.