By David Kiefer, MD, Editor

Clinical Assistant Professor, Department of Family Medicine, University of Wisconsin; Clinical Assistant Professor of Medicine, Arizona Center for Integrative Medicine, University of Arizona, Tucson

Dr. Kiefer reports no financial relationships relevant to this field of study.

SYNOPSIS: Using an online survey system, researchers showed that the use of psychedelics can increase feelings of connection to nature.

SOURCE: Kettner H, et al. From egoism to ecoism: Psychedelics increase nature relatedness in a state-mediated and context-dependent manner. Int J Env Res Public Health 2019;16:E5147.


A total of 654 people intending to use any of a number of psychedelic substances completed online surveys focusing on well-being and relatedness to nature.

The study participants were followed post-experience and were surveyed again the next day and two weeks, four weeks and two years afterward.

Post-experience, study participants showed a statistically significant increase in nature relatedness from baseline; there was a positive correlation between this increase and a variable termed ego dissolution.

A resurgence in the interest in psychedelic-assisted psychotherapy has brought an interesting array
of clinical trials to the forefront of the medical literature. For some difficult-to-treat conditions, such as post-traumatic stress disorder (PTSD), major depression, and addiction, clinical trials are starting to show promise.1,2,3

Worldwide, researchers are studying different types of psychedelics, inlucding natural sources of psilocybin, a hallucinogenic alkaloid compound, found in some species of mushrooms (colloquially known as “magic mushrooms”), as well as synthetic forms of psilocybin. In addition, researchers are focusing on the compound 3,4-methylenedioxymethamphetamine (MDMA) for the treatment of PTSD.3 Lysergic acid diethylamide (LSD) or “acid,” also has been studied in clinical trials for treating anxiety.4

Kettner et al tapped into the idea that many people have a disconnection from both the natural world and other people, which can be associated with, if not causally related to, a variety of physical and psychological health conditions. The researchers mused about the benefits of connectedness, and cited some preliminary evidence showing that psychedelic substances may increase feelings of connectedness, especially “nature relatedness,” and decrease psychological distress. In developing their hypothesis, the researchers mentioned a psychedelic mechanism of action (serotonin 2A receptor agonists) and the cultural aspects of global, traditional, and ceremonial use. They hoped to expand on the preexisting literature, perhaps to comment more on whether psychedelic use was associated with, or causative of, increased connections to nature through a large sample size using an online survey system.

To find study participants, the researchers advertised on “drug-related websites.” Participants were asked to sign up on the survey website if they were planning to use any of a number of hallucinogenic substances in the “near future.” (See Table 1.) Survey information was collected at baseline and after the psychedelic experience. See Table 2 for the specific information and surveys collected and their timing. At baseline, the researchers collected demographics and an assessment of lifetime psychedelic use. Scales for psychological well-being (Warwick-Edinburgh Mental Wellbeing Scale, or WEMWS) and nature relatedness (NR-6) also were administered at baseline. The day after the reported psychedelic experience, the researchers administered a mystical experience questionnaire to assess for variables, such as mood, time and space flexibility, and mystical feelings. Also, participants completed a survey exploring the dispersion of the ego, with subsets for quantifying fear, paranoia, isolation, and sensations of death or insanity.

Table 1. Hallucinogenic Substances

  • Psilocybin
  • Magic mushrooms/truffes
  • Lysergic acid diethylamide (LSD) or 1P-LSD
  • Ayahuasca
  • N, N-dimethyltryptamine (DMT)
    or 5-MeO-DMT
  • Salvia divinorum
  • Mescaline
  • Iboga or ibogaine

Table 2. Information and Surveys Collected


  • Demographics
  • Psychological well-being (Warwick-Edinburgh Mental Wellbeing Scale)
  • Nature relatedness scale (short form, NR-6)
  • Lifetime psychedelic use (categories, from never to > 100 times)

One day after psychedelic experience

  • Mystical experience questionnaire
  • Ego dissolution survey
  • Visual effects
  • Setting (presence in nature, effect of nature on experience)
  • Overall experience quality, rated from 0-100

Two and four weeks after psychedelic experience

  • Psychological well-being (Warwick-Edinburgh Mental Wellbeing Scale)
  • Nature relatedness scale (short form, NR-6)

Two years after psychedelic experience

  • Nature relatedness scale (short form, NR-6)
  • Question asking for number of additional psychedelic experiences

A total of 654 survey respondents completed the baseline evaluation. Of these, the average participant age was 28 years, and 74% were male. Geographic location of the respondents varied, with most (31%) in an “other” category, 30% from the United States, 20% from the United Kingdom, and lower percentages from Denmark, Germany, and Canada. Most respondents had prior psychedelic experiences, with a bell-shaped curve centered around two to 10 experiences total; 9.5% had never tried psychedelics; and 6.1% had tried them more than 100 times. Interestingly, nature relatedness, as per the NR-6 scale, correlated positively with lifetime psychedelic use (P < 0.0001), ranging from 3.52 to 4.45 (average 4.01).

Study participants were lost to follow-up. Only 379 people completed the surveys the day after the psychedelic experience, 315 at two weeks, 212 at four weeks, and 64 at two years. Of note, 47 of the 64 people who completed the assessment at two years had additional psychedelic experiences during that time (median = 2). Nature relatedness increased from a baseline average of 4.0 to 4.1 for both the two-week and four-week post-experience surveys, and this was determined to be a significant increase (P = 0.014). Of note, the researchers reported the baseline to be typically higher than similar demographics, making one question the study selection bias and generalizability of the results. This increase in nature relatedness was associated with increases in psychological well-being (as per the WEMWS), but mostly for the four-week post-experience time point (P < 0.0001). The effect size for the correlation at four weeks was calculated to be “moderate” whereas that at two weeks was merely “weak.”

The authors captured a variety of information from the other surveys, including the mystical experience, ego dissolution, setting, and visual effects surveys. They used statistical methods to predict which variables most affected nature relatedness. They drew from the “entire sample” for this analysis, but only 233 people were included. It is unclear how those people were chosen, but presumably it was because of the presence of, or lack of, survey data available. From this analysis, only the ego dissolution scores correlated significantly with nature relatedness over time (P = 0.014). Some trends regarding nature relatedness also surfaced and were not quite significant: perceived access to nature, and ego dissolution in the subgroup of people with nature relatedness scores below the mean (4.01 as per the NR-6).

When the researchers examined the survey results over time, they found that time was associated significantly with nature relatedness (P < 0.0001), namely that nature relatedness increased after psychedelic use. The scores for the different time points are listed in Table 3. Of note, there was some discrepancy in the NR-6 scores reported for the two- and four-week time points in the different parts of the study. Regardless, a slight increase, bordering on significant, seems to have transpired.

Table 3. Nature Relatedness Scores


NR-6 score



Two Weeks

4.13 (P = 0.046)

Four Weeks

4.28 (P = 0.052)

Two Years

4.38 (P < 0.0001)

Nature relatedness scores from the NR-6 across the different time points for the study, from baseline and three times post-psychedelic experience.
P values are when the value is compared to baseline.


In the lengthy introduction, the researchers cited dozens of papers focused on the importance of connection to nature for health and physical/mental well-being, as well as the emerging research on the physiological and clinical effects of some psychedelic substances. They tried to bring all of this together in their hypotheses: First, that those who have used psychedelics more would be more connected to nature, and second, that there would be an increase in nature relatedness, correlated with improved psychological parameters, after a psychedelic experience. Did they successfully show such results? The answer is a resounding “possibly!”

The effort was impressive, including the use of several different survey instruments, and attracting participants from a wide geographic range. The anonymous, online methodology exposed some flaws regarding the specifics of the study participants. Barring some basic demographic information and details about prior psychedelic use, the type of person who would participate in an online survey, especially given the current legal state of affairs for these substances in most countries, may carry a bias that would not necessarily have been controlled for in this study. Perhaps only the most eager psychedelic users, or only those with mostly positive experiences, would participate. Some of these safeguards may be lacking in this methodology.

Regarding the hypotheses, the researchers did find that lifetime psychedelic use correlated with nature relatedness (hypothesis 1) and that an increase in nature relatedness occurred after a psychedelic experience and persisted through to two years (hypotheses 1 and 2). Of course, with some participants continuing to use psychedelic substances after the initial time point, it is difficult to say if the two-year change represented “persistence.” This increase coexisted with an improvement in psychological well-being (hypothesis 2), and seems to have correlated with ego dissolution as per a survey centered on that variable. All of these results occurred for a small subset of the original participants; we need to remember the significant dropout rate (from 654 respondents to only 64 at the end) and wonder about those people who did not follow up after the psychedelic experience.

It seems that these results should be more tempered than as forwarded by the research team. The authors discussed a “causative role” for psychedelics in increasing nature relatedness. Without a control group and better tracking for the study dropouts, it would be difficult to draw this conclusion. The idea of “ego dissolution,” which also is mentioned in the title, is an interesting concept that begs follow-up questions such as “How much?,” “Is this safe?,” and “How long does this last?” Further description and quantification of this and the other surveys exploring the mystical experience side of this study would be helpful to a clinician faced with talking to patients about these substances. Furthermore, on the topic of safety, a complete assessment of this intervention should have asked participants about any symptoms or negative aspects of the psychedelic experience. Again, this complete picture of these substances would be helpful in further discussion of their potential clinical role to promote well-being.

There is no doubt that humans benefit from a connection to nature, though the specifics about how that is defined likely differ for the individual, the culture, and the geographic region. In addition, research is surfacing that tie a connection to the natural world with various indicators of psychological and physical well-being. Ways to promote this connection and improve health include the “greening” of hospitals, forest bathing, and urban gardens. Whether psychedelics have a role in nature relatedness or well-being remains to be seen, although this study seems to have contributed a few pieces to that puzzle. Perhaps some of the ongoing, more rigorous clinical trials on this topic will give clinicians the specific data they need to counsel patients about optimal ways to achieve nature relatedness and overall health and wellness.


  1. Carhart-Harris RL, et al. Psilocybin with psychological support for treatment-resistant depression: Six-month follow-up. Psychopharmacology (Berl) 2018;235:399-408.
  2. Johnson MW, et al. Long-term follow-up of psilocybin-facilitated smoking cessation. Am J Drug Alcohol Abuse 2017;43:55-60.
  3. Mithoefer MC, et al. MDMA-assisted psychotherapy for treatment of PTSD: Study design and rationale for phase 3 trials based on pooled analysis of six phase 2 randomized controlled trials. Psychopharmacology (Berl) 2019;236:2735-2745.
  4. Gasser P, et al. Safety and efficacy of lysergic acid diethylamide-assisted psychotherapy for anxiety associated with life-threatening diseases. J Nerv Ment Dis 2014;202:513-520.