This investigation presents two primary notable findings regarding prLSD among Americans. The first is that there is considerable variation in prLSD based on gender, race and ethnicity, education level, religious beliefs, marital status, sexual orientation, urbanicity, criminal justice involvement, personal history of LSD use, and other factors. The second is that Americans’ risk perception of LSD is declining among the general population, as well as most subpopulations analyzed. We will now place some of these findings into context and elaborate upon them, as well as their potential implications.
Our observation of elevated prLSD in people identifying as Black and Hispanic may explain the lower rates of LSD use among these groups compared to Whites.22 These findings are also notable since previous research has found lower risk perception of trying heroin among Blacks and Hispanics compared to Whites23, but higher risk perception of regular cannabis use.24 In line with our findings, a previous study found US-born Latinos and Latino immigrants had higher prLSD than US-born Whites and non-Latino White immigrants.25 One explanatory factor for higher prLSD in Blacks may be the significant research abuses carried out against this group in early LSD studies.26 Given the widespread use of psychedelics in ancient Mesoamerica, the higher prLSD in Hispanics is somewhat puzzling, though may be the result of opposition to psychedelic use among Spanish colonizers and the Catholic Church in South and Central America.27 This culminated not only in severe persecution of psychedelic users in New Spain, but also execution by the Spanish Inquisition for charges of idolatry, witchcraft, and paganism. This ultimately forced psychedelic use among the indigenous peoples of Mexico underground until R. Gordon Wasson exposed this in his 1957 Life magazine account, “Seeking the Magic Mushroom.”28
With approval by the US Food and Drug Administration of MDMA for posttraumatic stress disorder (PTSD) and psilocybin for treatment-resistant depression expected by 202429 and 202630, respectively, our findings on prLSD raise concerns that these novel treatments may not be as widely embraced by Black and Hispanic patients compared to White patients due to safety concerns. Of course, patients may view psychedelics as less risky when administered in a medical setting. However, the possibility of higher concerns about risks of psychedelic therapy is already being suggested by diversity-related recruitment challenges plaguing these trials in the US. Despite Whites making up 77% of the US population, they constituted 89% of psychedelic therapy trial participants in a 2018 study.31 Given that PTSD prevalence is highest among Blacks in the US32 and MDMA has demonstrated impressive efficacy for severe PTSD33, poor acceptability of MDMA-assisted therapy by Black patients would be particularly tragic. In what may be a hopeful finding on this front, we did identify linear decreasing trends in prLSD for nearly all racial and ethnic groups analyzed, including Blacks and Hispanics.
Our finding of an association between greater prLSD and older age is consistent with previous findings.6,16,34 In general, perceived risk of drugs increases with age. However, it seems likely that some of the higher prLSD among older Americans is attributable to the legacy of inflammatory social discourse on LSD in the 1960s, which centered around highly publicized claims about terrifying purported LSD side effects such as chromosomal damage, cancer, birth defects, and long term psychosis in users, which have not been supported by subsequent research.35–39
The association we observed between lower prLSD and identifying as a sexual minority is in line with previous findings among people who have never used LSD.40 Our identified association between higher education level and lower prLSD contrasts with previous studies showing positive associations between education level and perceived risk of marijuana and heroin.23 The relationship we observed between past year serious psychological distress and lower prLSD is intriguing since level of current psychological distress was not associated with perceived risk of marijuana, tobacco, or alcohol use in a previous study.41 However, medical marijuana users have higher rates of past month psychological distress than recreational users42, and daily marijuana use is more common in people with past month psychological distress.43 LSD use is more common among people with past year psychological distress44,45, and it is possible that the lower prLSD in this group might result from self-treatment of mental illness with LSD and associated learning about its risk profile to maximize efficacy and safety. However, this finding could also indicate decreased risk perception secondary to psychological distress and desperation for relief without high levels of knowledge about risk profile. Unfortunately, the NSDUH does not collect data on frequency of LSD use or reasons for use. Notably, we found people with past year suicide attempts were more likely to have higher prLSD, suggesting possible awareness among these individuals that LSD use could be potentially dangerous for them given rare reports of suicide following use.46
Over the study period there was a statistically significant linear decreasing trend (-5.7% from 2015–2019) in respondents reporting “great” prLSD. This trend was also observed in nearly all subgroups assessed. There was also a similar trend in respondents who believed using LSD weekly represents “great risk” (-5.0% from 2015–2019). Of the other substances for which perceived risk of weekly use was measured (binge alcohol use, cocaine, heroin, and marijuana), only marijuana experienced a larger drop in respondents reporting “great risk” over this period (-7.1%). This suggests LSD and marijuana are experiencing uniquely large reductions in societal risk perception.
Risk perception can be significantly impacted by both social context and objective drug knowledge47, and there appear to be significant social changes occurring around LSD use, while information about LSD is easier than ever to access. It is unclear to what degree decreasing prLSD may reflect wider knowledge around the importance of set and setting48 in reducing psychedelic-related harms. However, a relationship between risk perception and such knowledge has been observed in MDMA users.47 Notably, the number of “bad trips” experienced by LSD users fell dramatically from the mid-1960s through the 1970s49, possibly due to reduced expectations of having a bad trip after heated societal discourse shifted from LSD use to other topics after LSD possession was made illegal. However, this reduction could also reflect increased dissemination of harm reduction knowledge over time.
Given the ongoing reduction in prLSD, it is important to consider whether Americans are more realistically judging LSD’s risk profile. Though Americans perceive the risk of weekly use of LSD as being closer to that of heroin and cocaine than marijuana and alcohol, expert consensus has ranked LSD as among the least harmful drugs to users and others.17 The vast majority of LSD users do not experience serious adverse medical consequences, with 0.2% of use events resulting in emergency medical attention in a recent survey of more than 10,000 past year LSD users.50 In that study, the most common adverse events requiring medical attention were anxiety, panic, and confusion. Most LSD-related adverse events are mild or moderate51, with the majority resolving within 24 hours.50 LSD, like other serotonergic psychedelics, also has low addictive potential.15 It does not produce repetitive self-administration in animal models52 and physical dependence is extremely rare.53 Lifetime prevalence of hallucinogen use disorder, which also includes use of hallucinogens with more addictive potential such as 3,4-methylenedioxy-methamphetamine (MDMA), ketamine, and phencyclidine, is extremely low at 0.60% in the US.54 While accidental deaths55,56 among people taking LSD have been reported rarely, there is little evidence of lethal LSD overdose potential in physically healthy individuals, even at extremely high doses.57,58 Despite LSD use by tens of millions of Americans59, less than a handful of toxicity-related deaths have been reported, usually amid exacerbating circumstances such as massive overdose or use of police restraints.15,60,61 Legal risks of LSD use are also low considering how few people are arrested or imprisoned for LSD possession or trafficking.62,63 There still may be social repercussions for LSD use though. We are unaware of longitudinal data on social disapproval of LSD use among American adults. However, among American 12th graders, social disapproval of people 18 years of age and older trying LSD remains high, though it has been in steady decline since 2009, when it was 88.2%, falling to 68.7% in 2021, down significantly from the last measurement of 76.1% in 2019.64 Since psychedelic use has reached record levels in the US recently65, it seems probable that social acceptance of LSD use among American adults is also increasing, like that of marijuana.66 For further details on LSD-related adverse events see Supplemental Appendix 2.
Given the infrequent and usually transient nature of LSD-related harms, it is surprising that perceived risk of weekly LSD use remains only slightly lower than that of cocaine and heroin and nearly double that of weekly binge drinking, particularly when considering the significantly higher medical risk profile for these other drugs.67–69 One factor driving this discrepancy in regards to marijuana and alcohol might be LSD’s more consistent illicit status since illicit status of a drug may contribute to an unrealistically high perceived risk, which tends to decrease over time.70,71 In line with this, residents of states with medical marijuana laws have lower risk perceptions of marijuana than residents of states without them.72
With LSD use in the US growing recently11, it is intriguing to consider the potential contribution of decreased prLSD to this phenomenon. Though past studies indicate inverse associations between prLSD and rates of LSD use34, this relationship is not as clearcut as it may initially appear. Risk perception is only one of multiple factors contributing to decision-making about drug use. Availability, as well as descriptive norms (perception of frequency of use among peers), injunctive norms (peer approval), and sensation seeking are other important factors affecting drug use with varying levels of influence for different substances. Supporting the importance of other factors besides prLSD in decision-making around LSD use is a previous study that found 63% of young women who used LSD in the past year reported half or more of their peers used LSD, versus 3% for those who used marijuana but not LSD in the past year, and 1% for those who used neither.34 That study also found that young women who used LSD were less disapproving of people trying LSD than those who had used only marijuana or neither drug.
Changes in risk perception predict use of tobacco, alcohol, and cannabis.73 Previous population level studies of American adolescents suggest that changes in prLSD are a leading indicator of inverse changes in use.74,75 However, one survey of college students, which did not inquire about LSD, found that for designer drugs such as MDMA, injunctive norms, sensation seeking, and perceived availability were associated with past year use, while risk perception was not.76 Increased rates of use following decrease in risk perception (a phenomenon termed the “motivational hypothesis”) has been observed for multiple drugs.73 However, for marijuana, there is also evidence for the “risk reappraisal hypothesis”, in which users may readjust unrealistic risk perceptions about a drug following its use. People have also been observed to change expectancies around alcohol use following initial consumption.77 This may be the case with LSD. Strikingly, we found that lifetime LSD use conferred a 62% decrease in likelihood of respondent report of higher prLSD, the largest reduction of any factor analyzed. However, we do not know the prLSD of LSD users in this sample prior to first use. Unfortunately, we are unaware of research analyzing the directionality of the relationship between prLSD and LSD use at the individual level. Intriguingly, previous research on marijuana indicates that though there are differences in risk perception between users and non-users, risk perception among users is associated with neither frequency of use or experiencing drug-related consequences.78 Unfortunately, the NSDUH does not collect data on frequency of use or history of LSD-associated adverse events to allow for a similar investigation here.
In addition to prospectively gathering data on how prLSD changes following first LSD use, future studies on prLSD and its relationship with LSD use should gather data from participants on descriptive norms, injunctive norms, what they consider the most important risks of LSD to be, and whether they know someone who has experienced an LSD-related adverse effect. Additionally, data on LSD use frequency, history of adverse effects, and reasons for use should be collected from LSD users to better understand what bearing these factors have on prLSD. Finally, studies should prospectively investigate the relationship between prLSD in a cohort of people before and after initiation of naturalistic LSD use.
The potential effects of decreasing prLSD on American society’s relationship with LSD and other psychedelics in coming years are intriguing to consider. Should these trends continue, it is possible that LSD’s legal status could become liberalized in more jurisdictions, similar to what is occurring with psilocybin. Thus far though, LSD and other synthetic psychedelics have tended to be excluded from psychedelic decriminalization efforts, with Oregon’s drug decriminalization law, approved by voters in 2020, being a notable exception.79 Growth in public support for medical use of psychedelics may also result from prLSD. However, it is also possible that should prLSD continue to fall, there could be an increase in negative LSD-related outcomes, particularly if irresponsible use grows secondary to prLSD falling to levels inconsistent with actual harm potential. Should there be an increase in high profile LSD-related adverse events, we may also see a sensationalistic focus on these by the media, as occurred in the mid-1960s.80 If this occurs, there may then be a reversal of the decreasing prLSD trend, a softening of support for liberalization of LSD’s legal status, and diminishing receptivity to psychedelic-assisted therapy by both the general public and regulators.
Strengths and Limitations
The primary strength of this study is its use of data from multiple administrations of a large, rigorously conducted survey employing a nationally representative sample. Limitations include use of retrospective self-reported data. However, the NSDUH’s substance use self-report measures have high concordance with drug testing results.81 The NSDUH’s restriction of respondents to the civilian non-institutionalized population of the US is another important limitation. While this represents 97% of the US population21, the NSDUH excludes people in institutional settings such as hospitals, prisons, nursing homes, and addiction treatment centers, who are likely to have important demographic and prLSD differences.