The authors have declared that no competing interests exist.
Conceived and designed the experiments: TSK PØJ. Analyzed the data: TSK. Wrote the paper: PØJ TSK.
The classical serotonergic psychedelics LSD, psilocybin, mescaline are not known to cause brain damage and are regarded as non-addictive. Clinical studies do not suggest that psychedelics cause long-term mental health problems. Psychedelics have been used in the Americas for thousands of years. Over 30 million people currently living in the US have used LSD, psilocybin, or mescaline.
To evaluate the association between the lifetime use of psychedelics and current mental health in the adult population.
Data drawn from years 2001 to 2004 of the National Survey on Drug Use and Health consisted of 130,152 respondents, randomly selected to be representative of the adult population in the United States. Standardized screening measures for past year mental health included serious psychological distress (K6 scale), mental health treatment (inpatient, outpatient, medication, needed but did not receive), symptoms of eight psychiatric disorders (panic disorder, major depressive episode, mania, social phobia, general anxiety disorder, agoraphobia, posttraumatic stress disorder, and non-affective psychosis), and seven specific symptoms of non-affective psychosis. We calculated weighted odds ratios by multivariate logistic regression controlling for a range of sociodemographic variables, use of illicit drugs, risk taking behavior, and exposure to traumatic events.
21,967 respondents (13.4% weighted) reported lifetime psychedelic use. There were no significant associations between lifetime use of any psychedelics, lifetime use of specific psychedelics (LSD, psilocybin, mescaline, peyote), or past year use of LSD and increased rate of any of the mental health outcomes. Rather, in several cases psychedelic use was associated with lower rate of mental health problems.
We did not find use of psychedelics to be an independent risk factor for mental health problems.
Psychedelic plants have been used for celebratory, religious or healing purposes for thousands of years
This study was exempt from review by our Regional Committee for Medical Research Ethics because all data are available in the public domain without any identification of personal information. The National Survey on Drug Use and Health (NSDUH) was approved by an institutional review board of the Research Triangle Institute.
The annual NSDUH survey provides estimates of substance use and mental health indicators from a randomly-selected sample representative of the general US civilian non-institutionalized adult population. The Substance Abuse and Mental Health Services Administration of the US Department of Health and Human Services is responsible for the NSDUH study design and methods of assessment. Trained interviewers met the randomly-selected participants in their homes, and participants listened to recorded questions via headphones and then entered their answers directly into a computer, providing a highly confidential and standardized setting. We pooled data from NSDUH survey years 2001 to 2004 because in these years participants were asked about symptoms of a range of psychiatric disorders and about whether they have been exposed to an extremely stressful event. We excluded half of the participants from year 2004 because of changes in the survey questions. We restricted the samples to adults aged 18 years and older because younger participants were asked different mental health questions than adults. The response rate was 78%. In addition, approximately 10% of participants were excluded from the public use data file, either because of excessive missing data on drug use or because they were excluded at random in order to increase anonymity. Detailed information on the sampling and data collection methods, including interview instructions and questionnaires, confidentiality and informed consent are available at the NSDUH website (
We counted participants as having any lifetime psychedelic use if they affirmed use of LSD, psilocybin, mescaline, or peyote. We also examined use of each of the substances separately. Mescaline and peyote was combined into one category “mescaline/peyote” because mescaline is the active substance in peyote cactus, but peyote was also examined separately. Information was also available on past year use of LSD, but not past year use of psilocybin or mescaline. LSD, psilocybin, and mescaline are all classical serotonergic psychedelics with main mechanism of action at the serotonin 2A receptor
The K6 scale provides a valid assessment of general psychological distress during the worst month of the past year, that are common to a broad range of psychiatric disorders, with strong accuracy in discriminating between people with and without one or more diagnoses from the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV
Past year mental health treatment was divided into four outcome variables: inpatient mental health treatment, outpatient mental health treatment, psychiatric medication prescription, and felt a need but did not receive mental health treatment. Inpatient mental health treatment included overnight stays for alcohol or drug problems at hospitals or rehabilitation centers. Outpatient mental health treatment included treatment for alcohol or drug problems at rehabilitation centers, mental health centers, emergency rooms, doctors’ offices, prisons or jails, or self-help groups. Data was not available on medication prescription for alcohol or drug problems. Needed but did not receive mental health treatment included respondents who felt that they needed treatment for alcohol or drug problems but did not receive any such treatment.
Symptoms indicators for eight DSM-IV psychiatric disorders were evaluated using the short form of the World Health Organization Composite International Diagnostic Interview (CIDI-SF)
We selected control variables based on associations with mental health in previous research
We used multivariate logistic regression to calculate associations between the past year mental health indicators and use of psychedelics, including lifetime use of any psychedelics, lifetime use of LSD, psilocybin, mescaline/peyote, or peyote, and past year use of LSD. We also calculated the associations between the past year mental health indicators and lifetime use of any psychedelics in the presence or absence of other risk factors in stratified subgroups (sex, age, past year illicit drug use, lifetime exposure to an extremely stressful event). Participants with missing data on relevant mental health outcomes or past year illicit drug use were excluded.
The estimated associations between the use of psychedelics are presented as adjusted odds ratios (aOR), 95% confidence intervals (CI), and
We used a standard alpha of 0.05; however any significant results should be considered in the context of the number of statistical analysis performed. It is typically recommended to have at least 10 events per predictor variable for multivariate logistic regression, although recent simulation studies suggest as few as 5 events per predictor variable is sufficient
The sample consisted of 130,152 respondents, of which 21,979 (13.4% weighted) reported lifetime use of any psychedelic.
Among used psychedelics | Among not used psychedelics | Used psychedelics, within each category | |||
wt % | N | wt % | N | wt % | |
100% | 21967 | 100% | 108034 | 13.4% | |
18 to 25 years old | 20.6% | 11810 | 13.9% | 51000 | 18.7% |
26 years or older | 79.4% | 10157 | 86.1% | 57034 | 12.5% |
Male | 61.0% | 12736 | 45.9% | 48052 | 17.1% |
Female | 39.0% | 9231 | 54.1% | 59982 | 10.0% |
White | 85.7% | 18399 | 69.5% | 71732 | 16.0% |
Hispanic | 6.7% | 1679 | 12.4% | 14926 | 7.7% |
Black | 4.0% | 621 | 12.2% | 14331 | 4.8% |
Asian | 1.0% | 250 | 4.3% | 3843 | 3.4% |
Native American | 0.9% | 399 | 0.4% | 1060 | 25.2% |
Native Hawaiian or Pacific Islander | 0.2% | 77 | 0.3% | 492 | 9.6% |
More than one | 1.4% | 542 | 0.9% | 1650 | 20.0% |
Less than $20,000 | 17.2% | 5403 | 20.2% | 27777 | 12.2% |
$20,000 to $49,000 | 36.3% | 8616 | 38.0% | 42340 | 13.2% |
$50,000 to $74,999 | 19.6% | 3664 | 18.0% | 17953 | 15.0% |
$75,000 or more | 26.8% | 4284 | 23.8% | 19964 | 15.4% |
Not high school graduate | 13.2% | 3727 | 18.0% | 19174 | 10.2% |
High school graduate | 30.5% | 7265 | 32.3% | 36988 | 12.8% |
Some college | 29.7% | 6757 | 24.3% | 29775 | 15.9% |
College graduate | 26.6% | 4217 | 25.4% | 22056 | 14.0% |
Not married | 54.6% | 14978 | 41.3% | 62086 | 17.0% |
Married | 45.4% | 6985 | 58.7% | 45912 | 10.7% |
Never | 24.5% | 4486 | 53.7% | 48090 | 6.6% |
Seldom | 45.2% | 9662 | 34.2% | 40565 | 17.0% |
Sometimes | 27.3% | 6780 | 11.1% | 17174 | 27.6% |
Always | 3.1% | 1017 | 1.1% | 1922 | 31.1% |
No | 47.7% | 10951 | 66.1% | 71039 | 10.1% |
Yes | 52.3% | 10938 | 33.9% | 36361 | 19.3% |
Cannabis | 98.2% | 21542 | 33.0% | 42705 | 31.5% |
Opiates | 46.2% | 11249 | 7.7% | 10958 | 48.1% |
Cocaine | 70.1% | 14014 | 6.7% | 6959 | 61.8% |
Tranquilizers and sedatives | 44.1% | 8863 | 4.7% | 5131 | 59.2% |
Stimulants | 41.8% | 8648 | 3.7% | 4455 | 63.3% |
MDMA | 24.7% | 8074 | 1.2% | 2680 | 75.9% |
Inhaled anesthetics | 28.5% | 7515 | 1.6% | 2735 | 74.0% |
Alkyl nitrites | 19.8% | 3448 | 1.3% | 1283 | 70.3% |
Other inhalants | 12.8% | 2999 | 1.6% | 2750 | 55.6% |
PCP | 21.0% | 3752 | 0.4% | 481 | 89.3% |
Wt %, weighted percentage.
Among used psychedelics | Among not used psychedelics | Used psychedelics, within each category | |||
wt % | N | wt % | N | wt % | |
100% | 21967 | 100% | 108034 | 13.4% | |
LSD | 80.1% | 17486 | 0% | 0 | 100% |
Psilocybin | 61.5% | 14413 | 0% | 0 | 100% |
Mescaline/peyote | 37.8% | 6254 | 0% | 0 | 100% |
Peyote | 19.6% | 3120 | 0% | 0 | 100% |
LSD past year | 1220 | 0 | 100% | ||
Cannabis | 98.2% | 21542 | 33.0% | 42705 | 31.5% |
Opiates | 46.2% | 11249 | 7.7% | 10958 | 48.1% |
Cocaine | 70.1% | 14014 | 6.7% | 6959 | 61.8% |
Tranquilizers and sedatives | 44.1% | 8863 | 4.7% | 5131 | 59.2% |
Stimulants | 41.8% | 8648 | 3.7% | 4455 | 63.3% |
MDMA | 24.7% | 8074 | 1.2% | 2680 | 75.9% |
Inhaled anesthetics | 28.5% | 7515 | 1.6% | 2735 | 74.0% |
Alkyl nitrites | 19.8% | 3448 | 1.3% | 1283 | 70.3% |
Other inhalants | 12.8% | 2999 | 1.6% | 2750 | 55.6% |
PCP | 21.0% | 3752 | 0.4% | 481 | 89.3% |
Wt %, weighted percentage.
Ever used psychedelics | Never used psychedelics | |||||
wt % | N | wt % | N | Adjusted OR |
p | |
K6-scale | 15.5% | 3826 | 7.5% | 10389 | 1.0 (0.9–1.1) | 0.72 |
Inpatient | 2.9% | 708 | 0.9% | 1135 | 0.9 (0.7–1.2) | 0.53 |
Outpatient | 15.2% | 3343 | 6.5% | 7739 | 0.9 (0.8–1.0) | 0.13 |
Medication | 16.3% | 3320 | 9.1% | 9135 | 0.9 (0.8–1.0) | 0.05 |
Needed but did not receive | 11.9% | 2979 | 4.2% | 6320 | 0.9 (0.8–1.1) | 0.31 |
Panic disorder | 16.5% | 4018 | 8.5% | 10867 | 1.0 (0.9–1.1) | 0.62 |
Major depressive episode | 6.8% | 1640 | 2.7% | 3828 | 1.0 (0.8–1.2) | 0.80 |
Mania | 1.9% | 407 | 0.7% | 717 | 1.1 (0.8–1.6) | 0.53 |
Social phobia | 1.4% | 302 | 0.6% | 690 | 0.9 (0.7–1.3) | 0.76 |
Generalized anxiety disorder | 3.2% | 739 | 1.4% | 1770 | 0.9 (0.7–1.1) | 0.31 |
Agoraphobia | 1.4% | 320 | 0.7% | 853 | 1.0 (0.6–1.6) | 0.90 |
Posttraumatic stress disorder | 3.2% | 649 | 1.2% | 1456 | 1.0 (0.8–1.3) | 0.86 |
Non-affective psychosis |
4.4% | 658 | 1.8% | 1451 | 0.8 (0.6–1.1) | 0.21 |
Heard voices others could not | 4.3% | 639 | 2.1% | 1628 | 1.0 (0.8–1.4) | 0.82 |
Felt force taking over mind | 2.3% | 324 | 0.9% | 736 | ||
Felt force inserting thoughts | 1.0% | 159 | 0.5% | 328 | 0.7 (0.5–1.2) | 0.23 |
Felt force steal thoughts | 1.3% | 230 | 0.7% | 547 | 0.7 (0.5–1.2) | 0.21 |
Force used special signals | 3.3% | 508 | 1.3% | 1195 | 0.9 (0.7–1.2) | 0.50 |
Believed plot to harm you | 2.1% | 332 | 0.9% | 732 | 0.8 (0.5–1.2) | 0.22 |
Saw vision others could not | 4.0% | 604 | 1.8% | 1525 | 1.0 (0.7–1.3) | 0.77 |
Adjusted for age, gender, race/ethnicity, income, education, married, risky behavior, extremely stressful event, and ten types of lifetime drug use (cannabis/marijuana, opiates, cocaine, sedatives/tranquilizers, stimulants, MDMA/ecstasy, inhaled anesthetics, amyl nitrates, other inhalants, PCP).
Data on symptoms of non-affective psychosis available only for years 2001–2002.
Bold indicates p<0.05.
Lifetime use | Past year use | |||||||||
LSD | Psilocybin | Mescaline/peyote | Peyote | LSD | ||||||
Adjusted OR |
p | Adjusted OR |
p | Adjusted OR |
p | Adjusted OR |
p | Adjusted OR |
||
K6-scale | 1.0 (0.9–1.1) | 0.65 | 0.04 | 0.9 (0.7–1.0) | 0.09 | |||||
Inpatient | 0.9 (0.6–1.2) | 0.31 | 0.8 (0.6–1.0) | 0.07 | 0.9 (0.6–1.2) | 0.41 | 1.0 (0.6–1.5) | 0.96 | ||
Outpatient | 0.9 (0.8–1.0) | 0.10 | 0.9 (0.8–1.1) | 0.23 | 0.9 (0.7–1.1) | 0.17 | 0.9 (0.7–1.2) | 0.46 | ||
Medication | 0.9 (0.7–1.2) | 0.44 | ||||||||
Needed but did not receive | 1.0 (0.9–1.1) | 0.47 | 0.9 (0.8–1.1) | 0.44 | 0.8 (0.7–1.0) | 0.08 | 1.0 (0.8–1.4) | 0.93 | ||
Panic attacks | 0.9 (0.9–1.1) | 0.30 | 1.0 (0.9–1.2) | 0.98 | 1.0 (0.8–1.1) | 0.61 | 0.8 (0.6–1.0) | 0.09 | ||
Major depressive episode | 1.0 (0.8–1.1) | 0.61 | 0.9 (0.8–1.1) | 0.18 | 0.9 (0.7–1.0) | 0.14 | 0.9 (0.7–1.2) | 0.67 | 0.8 (0.5–1.1) | 0.21 |
Mania | 1.2 (0.9–1.8) | 0.23 | 0.8 (0.6–1.0) | 0.08 | 0.8 (0.6–1.2) | 0.24 | 0.8 (0.5–1.2) | 0.22 | 0.8 (0.5–1.3) | 0.33 |
Social phobia | 1.0 (0.6–1.5) | 0.93 | 0.8 (0.5–1.1) | 0.20 | 0.7 (0.5–1.0) | 0.06 | 1.0 (0.6–1.6) | 0.90 | 1.2 (0.6–2.4) | 0.61 |
Generalized anxiety disorder | 0.9 (0.7–1.1) | 0.30 | 0.8 (0.7–1.1) | 0.19 | 0.9 (0.7–1.1) | 0.31 | 0.9 (0.7–1.3) | 0.63 | 1.1 (0.6–1.7) | 0.85 |
Agoraphobia | 1.0 (0.6–1.7) | 0.94 | 0.8 (0.5–1.2) | 0.27 | 1.1 (0.7–1.7) | 0.75 | 0.7 (0.3–1.4) | 0.26 | ||
Posttraumatic stress disorder | 1.2 (1.0–1.6) | 0.08 | 0.9 (0.7–1.2) | 0.41 | 0.9 (0.7–1.2) | 0.36 | 0.9 (0.6–1.2) | 0.41 | 1.0 (0.6–1.6) | 0.92 |
Non–affective psychosis |
0.9 (0.7–1.2) | 0.51 | 0.9 (0.6–1.2) | 0.42 | 0.8 (0.6–1.1) | 0.27 | 0.8 (0.6–1.1) | 0.17 | 0.9 (0.6–1.3) | 0.51 |
Heard voices | 1.0 (0.7–1.3) | 0.73 | 1.0 (0.8–1.3) | 0.94 | 0.9 (0.6–1.3) | 0.55 | 0.8 (0.6–1.3) | 0.45 | 0.8 (0.6–1.3) | 0.41 |
Felt force taking over mind | 0.7 (0.5–1.0) | 0.08 | 0.9 (0.5–1.4) | 0.54 | 0.7 (0.4–1.3) | 0.26 | ||||
Felt force inserting thoughts | 0.9 (0.6–1.5) | 0.72 | 0.7 (0.4–1.2) | 0.23 | 1.2 (0.7–1.8) | 0.51 | 1.3 (0.8–2.3) | 0.31 | 1.7 (0.8–3.5) | 0.19 |
Felt force steal thoughts | 0.9 (0.5–1.5) | 0.62 | 0.8 (0.5–1.4) | 0.48 | 0.8 (0.4–1.5) | 0.47 | 0.7 (0.4–1.1) | 0.08 | 1.3 (0.7–2.5) | 0.36 |
Force used special signals | 0.9 (0.7–1.3) | 0.73 | 0.9 (0.7–1.3) | 0.60 | 1.0 (0.8–1.4) | 0.84 | 1.1 (0.8–1.5) | 0.69 | 1.4 (1.0–1.9) | 0.06 |
Believed plot to harm you | 0.9 (0.6–1.3) | 0.62 | 1.0 (0.6–1.5) | 0.65 | 0.9 (0.6–1.5) | 0.66 | 0.8 (0.4–1.4) | 0.38 | 1.1 (0.6–1.9) | 0.82 |
Saw vision | 1.0 (0.8–1.3) | 0.91 | 0.9 (0.7–1.3) | 0.66 | 0.9 (0.7–1.2) | 0.50 | 0.8 (0.5–1.0) | 0.08 | 1.3 (0.8–2.1) | 0.22 |
Adjusted for age, gender, race/ethnicity, income, education, married, risky behavior, extremely stressful event, and ten types of lifetime drug use (cannabis/marijuana, opiates, cocaine, sedatives/tranquilizers, stimulants, MDMA/ecstasy, inhaled anesthetics, amyl nitrates, other inhalants, PCP).
Adjusted for above variables plus nine types of past year drug use (cannabis/marijuana, opiates, cocaine, sedatives/tranquilizers, stimulants, MDMA/ecstasy, inhalants, PCP).
Data on symptoms of non-affective psychosis available only for years 2001–2002.
Bold indicates p<0.05.
Lifetime psychedelic use was not significantly associated with serious psychological distress in the worst month of the past year. Among the specific psychedelics, lifetime psilocybin use (aOR 0.8,
Lifetime psychedelic use was not significantly associated with any of the mental health treatment variables. Among the specific psychedelics there were a number of significant associations with lower rate of receiving or needing mental health treatment. Lifetime LSD use was significantly associated with a lower rate of outpatient mental health treatment (aOR 0.9,
Lifetime psychedelic use was not significantly associated with any of the eight past year psychiatric symptom indicators (aOR range 0.8 to 1.1), and lifetime psychedelic use was significantly associated with a lower rate of one of the seven psychotic symptoms (“Felt a force taking over your mind”: aOR 0.7,
In a series of multivariate logistic regression analyzes stratified by gender (male; female), age (18 to 25 years; 26 and older), any past year illicit drug use (no; yes), or lifetime extremely stressful event ever (no; yes) there were no significant associations with lifetime psychedelic use and greater risk of any of the mental health outcomes. Rather, in twelve cases there was an association with psychedelic use and lower rate of various mental health outcomes; however, most of these cases had marginal statistical significance (0.05<
Native Americans reported a high rate of lifetime psychedelic use (25%, weighted), with a high rate of lifetime peyote use (14%, weighted). However, less than 1% of lifetime psychedelic users and less than 3% of lifetime peyote users were Native Americans. Many Native Americans use peyote within legally-protected religious practice
On each analysis, less than 2% of participants were missing data. Including participants with missing data by setting missing data to “no” or “0” had a minimal effect on the results (less than 4% change in adjusted odds ratios, on average) and had no effect on statistical significance.
We found no relation between lifetime use of psychedelics and any undesirable past year mental health outcomes, including serious psychological distress, mental health treatment (inpatient, outpatient, medication, felt a need but did not receive), or symptoms of panic disorder, major depressive episode, mania, social phobia, generalized anxiety disorder, agoraphobia, posttraumatic stress disorder, or non-affective psychosis. In addition to not being significantly different from no association, in all cases the calculated adjusted odds ratios (aOR) were small (for all, psychedelic use aOR ≤1.2). Stratifying by age, gender, past year illicit drug use, or lifetime extremely stressful event did not substantially change the results of any of the logistic regression analyses. Likewise, lifetime use of LSD, psilocybin, mescaline, or peyote, or past year use of LSD, was not associated with a higher rate of mental health problems. There were a number of weak associations between use of any psychedelic or use of specific psychedelics and lower rate of mental health problems; these results might reflect beneficial effects of psychedelic use, relatively better initial mental health among people who use psychedelics, or chance “false positive” findings. Our results are consistent with assessments of the harm potential of psychedelics
This study had a retrospective, cross-sectional design, making it impossible to draw causal inferences. Many potentially important risk factors, such as family mental health history, were not available. Longitudinal data were not available on mental health or other factors before psychedelic use. We cannot exclude the possibility that use of psychedelics might have a negative effect on mental health for some individuals or groups, perhaps counterbalanced at a population level by a positive effect on mental health in others. We did not adjust for multiple comparisons, so some of the associations with weak statistical significance are likely due to chance. Screening questions, rather than diagnostic interviews, were used as symptom indicators. Self-reports of drug use behaviors and mental health questions could be influenced by memory errors and under-reporting; however, a 14-year longitudinal study reported good consistency over time in reporting of LSD use
The lack of association between the use of psychedelics and indicators of mental health problems in this large population survey is consistent with clinical studies in which LSD or other psychedelics have been administered to healthy volunteers
A case-control study of Native Americans failed to find any evidence of cognitive or mental health deficits among people who regularly used peyote in religious services compared to those who did not use peyote, rather total lifetime peyote use (mean 300 occasions, range 150–500) was associated with overall better mental health
In this study, lifetime use of psychedelics and past year use of LSD was not associated with past year symptoms of visual phenomena (“seeing something others could not”), panic attacks, psychosis, or overall serious psychological distress. Thus, our findings does not support either the idea of “flashbacks” described in extreme cases as recurrent psychotic episodes, hallucinations, or panic attacks, or the more recent “hallucinogen persisting perceptual disorder” (HPPD) described as persistent visual phenomena with accompanying anxiety and distress. All of the purported symptoms of HPPD are also present in people who have never used psychedelics
Case reports of long-term psychiatric problems attributed to LSD, include psychosis, panic attacks, other anxiety disorders, and depression
The Substance Abuse and Mental Health Data Archive provided the data files from the National Survey on Drug Use and Health, which was sponsored by the Office of Applied Studies of the Substance Abuse and Mental Health Services Administration.