Psychedelics not linked to mental health problems or suicidal behavior: A population study

This 2015 observational survey study (n=135.000) investigated the association between lifetime psychedelic use (LSD, psilocybin, mescaline) and mental health problems, but found no indication of the increased likelihood for psychological distress, mental health treatment, suicidal behaviour, depression, or anxiety amongst psychedelic users (n=19.300). These results contest the justification for prohibiting psychedelics as a public health measure.


Introduction: A recent large population study of 130,000 adults in the United States failed to find evidence for a link between psychedelic use (lysergic acid diethylamide, psilocybin or mescaline) and mental health problems.

Methods: Using a new data set consisting of 135,095 randomly selected United States adults, including 19,299 psychedelic users, we examine the associations between psychedelic use and mental health.

Results: After adjusting for sociodemographics, other drug use and childhood depression, we found no significant associations between lifetime use of psychedelics and increased likelihood of past year serious psychological distress, mental health treatment, suicidal thoughts, suicidal plans and suicide attempt, depression and anxiety. We failed to find evidence that psychedelic use is an independent risk factor for mental health problems.

Discussion: Psychedelics are not known to harm the brain or other body organs or to cause addiction or compulsive use; serious adverse events involving psychedelics are extremely rare. Overall, it is difficult to see how prohibition of psychedelics can be justified as a public health measure.”

Authors: Pål-Ørjan Johansen & Teri Suzanne Krebs



A study of 135,095 randomly selected United States adults found no significant associations between lifetime use of psychedelics and increased likelihood of past year serious psychological distress, mental health treatment, suicidal thoughts, suicidal plans and suicide attempt, depression and anxiety.


LSD, psilocybin and mescaline are classical psychedelics that act at the serotonin 2A (5-HT2A) receptor. They have similar effects and are cross-tolerance.

Psychedelics are not known to harm the brain or other body organs, cause addiction or compulsive use, or cause public order problems. They are well known for inducing profound effects on the mind, but are less harmful than alcohol and other controlled substances.

Psychedelics are used for mystical experiences, personal development, and in some countries, religious groups have protection from prosecution on grounds of freedom of belief or religion. However, modern antipsychedelic legislation began 100 years ago when members of rival religious groups campaigned against Native American peyote use.

There is increasing interest in the therapeutic use of psychedelics, especially for alcoholism, smoking cessation, depression and other mental health problems. However, prohibition has impeded scientific research and medical treatment development with psychedelics.

We examined the associations between psychedelic use and mental health using a new large data set, which included data on suicidal thoughts and suicide attempt.

Source, population and data

The National Survey on Drug Use and Health collected data on substance use and mental health from 135,095 respondents aged 18 years and over. 13.6% reported lifetime use of a psychedelic substance.

Use of psychedelics

We counted participants as having used psychedelics if they reported using LSD, psilocybin, mescaline or peyote, and separately examined peyote use.

Mental health indicators

We examined 11 self-reported indicators of past year mental health problems, including serious psychological distress during the worst month of the past year, mental health treatment, and physician diagnosis of depression and anxiety disorder.

The K6 scale provides a valid assessment of general psychological distress and is used to discriminate between people with and without psychiatric disorders.

The control variables included sociodemographic, psychological and drug use variables, and were selected on the basis of associations with mental health in previous research. Participants with missing data were excluded.

We included 11 control variables, including age, gender, race/ethnicity, household income, education, marital status, likes to test self by doing risky things, depressive episode before age 18 years, and 10 types of lifetime drug use.

Data analysis

We used multivariate logistic regression to calculate associations between mental health variables and lifetime use of any psychedelics, lifetime use of the specific psychedelics and past year use of LSD.

Lifetime psychedelic use was not associated with any indicators of mental health problems, but was associated with a lower likelihood of past year inpatient mental health treatment.

Specific psychedelic use

Among the specific psychedelics, psilocybin use was associated with lower likelihood of mental health problems, inpatient mental health treatment and psychiatric medication prescription, and past year use of LSD was associated with lower likelihood of serious psychological distress.

Mescaline/peyote use was associated with a greater likelihood of past year symptoms of major depressive episode, but not with diagnosis of depression.

Stratified subgroups

There were eight associations between psychedelic use and decreased likelihood of various past year mental health problems, most with weak statistical significance, but none consistent with the stratified subgroups in our previous population study.

Lack of associations with mental health or suicidality

We did not find any associations between lifetime use of psychedelics and mental health problems, receiving or needing mental health treatment, depression, anxiety, or suicidal thoughts or behavior in the past year.

The idea of ‘flashbacks’ and ‘hallucinogen persisting perceptual disorder’

We found no evidence for either flashbacks or the more recent ‘hallucinogen persisting perceptual disorder’ (HPPD) in our previous population study, and interviews with over 500 regular participants in Native American peyote ceremonies did not identify anyone with flashbacks or persistent visual symptoms.

Psychedelics and personally significant experiences

The results of this study may reflect beneficial effects of psychedelic use, better initial mental health among people who use psychedelics or chance ‘false positive’ findings. However, it is well documented that psychedelics elicit spiritual experiences and long-term psychological benefits have been reported in several clinical trials of LSD.


This study used screening questions rather than diagnostic interviews to assess mental health and behavior in people who had used psychedelics. It is impossible to draw causal inferences because many potentially important risk factors were not available, and longitudinal data were not available on mental health or other factors before psychedelic use. The use of dimethyltryptamine (DMT) in ayahuasca could not be determined from the data set, however, recent studies of people who have used ayahuasca hundreds of times have not detected evidence of problems.

Lack of association with suicidal behavior

There is little evidence linking psychedelic use to later suicide. A study of 178 adolescents with psychosis found that those who had used LSD were more likely to attempt suicide.

Some people have assumed that taking psychedelics could lead to depression and suicide, but there is now greater acceptance of introspective practices. A small number of publicized cases have been reported where relatives or anti-psychedelic campaigners have blamed an individual’s suicide on prior psychedelic use, without evidence of any clear connection. However, the rate of adverse events following clinical treatment with LSD was considered to be similar to that expected among patients.

Suicide is one of the most common causes of death in the general population, and it is extremely rare to experience suicide or death due to other causes while on psychedelics.

Comments on the history of national and international control of psychedelics

Concern about psychedelic use seems to have been based on media sensationalism, lack of information and cultural biases, rather than evidence-based harm assessments. In the early 20th century, psychiatrists viewed psychedelics as dangerous and delusional. One of their most prominent critics, Sidney Cohen, commented on his own LSD experience: ‘I got a massive jolt that I’ll never forget.’

The original World Health Organization (WHO) assessment of psychedelics claimed that psychedelics caused a list of problems, but the references cited included no evidence of harm from psilocybin, mescaline or DMT, and only a small number of case reports and anecdotes of possibly LSD-related adverse effects.

The British Medical Association noted that the classification and legal status of illegal drugs does not directly relate to the health risks they pose to users and communities. The UK Home Office acknowledged that LSD use was a sincere spiritual practice. We found no evidence linking past year LSD use to increased likelihood of inpatient mental health treatment in the UK assessment.

The US National Institute of Mental Health noted that people who use LSD repetitively in a social pattern ‘cannot be characterized by any specific psychiatric label’ and called for more scientific study of hallucinogen-derived mystical experiences. LSD, psilocybin, mescaline and several other psychedelics are included in Schedule I of the US Controlled Substances Act of 1970. The War on Drugs may have been a political decision rather than a public health decision.


The results of this study are consistent with previous population studies, early and recent randomized controlled trials, studies of regular participants in legally recognized psychedelic religious ceremonies, and recent expert assessments of drug harms. There is little evidence linking psychedelic use to lasting mental health problems.

Declaration of Conflicting Interests

The authors declare potential conflicts of interest regarding their work with EmmaSofia and the Association for a Humane Drug Policy.

Study details

Compounds studied
Mescaline LSD Psilocybin

Topics studied

Study characteristics
Observational Longitudinal Survey

135095 Humans

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