People who had recently used psychedelics such as psilocybin report a sustained improvement in mood and feeling closer to others after the high has worn off, shows a new Yale study published the week of Jan. 20 in the journal Proceedings of the National Academy of Sciences.
The results of a field study of more than 1,200 people attending multi-day arts and music festivals in the United States and United Kingdom confirm previous laboratory research indicating that psychedelic substances enhance feelings of social connectedness and improve mental well-being, the authors say.
“Our results show that people who take psychedelics ‘in the wild’ report positive experiences very similar to those observed in controlled laboratory studies,” said Yale’s Matthias Forstmann, postdoctoral fellow and first author of the paper.
Senior author and assistant professor of psychology Molly Crockett and her team visited a half dozen festivals and asked attendees who were not then under the influence of psychedelics about their recent social experiences, mood and substance use. By surveying them, the researchers were able to characterize the psychological effects of the “afterglow” of psychedelic experiences.
The team found that people who recently took psychedelics such as LSD and psilocybin, more commonly known as magic mushrooms, were more likely to report having “transformative experiences” so profound that they came out of the experience radically changed, including changes to their moral values.
Transformative experiences, in turn, were associated with feelings of social connectedness and positive mood. The most pronounced effects were reported by psychedelics users who had taken the drugs within the past 24 hours.
People who abstained from substance use, drank alcohol or took other drugs such as cocaine or opioids did not report transformative experiences, increased connectedness with others or positive mood to the same degree, the study showed.
By surveying them, the researchers were able to characterize the psychological effects of the “afterglow” of psychedelic experiences.
Crockett cautioned that the study was not designed to assess the negative reactions to the use of psychedelics that have been reported.
Further studies are necessary to learn which environmental factors are associated with positive versus negative psychedelic experiences, she said. But the findings add to a body of evidence suggesting psychedelic substances may have potential as therapy for mood disorders.
“We are encouraged that our study is consistent with previous laboratory findings showing mood benefits of psychedelics in healthy people and in patients suffering from anxiety and depression,” she said.
Funding: The research was conducted as part of The Experience Project funded by the John Templeton Foundation.
The practice of microdosing psychedelics involves ingesting sub-hallucinogenic amounts of a psychedelic substance (e.g. LSD, psilocybin) and has recently grown in popularity. The number of popular media accounts and book-length treatments of microdosing has been growing [1–7].
Online microdosing communities have grown to the tens of thousands with more than 40,000 users subscribing to the /r/microdosing subreddit (/r/microdosing subreddit, Reddit Inc, San Francisco, CA, USA).
This public interest speaks to a social need for scientific studies to inform the public about the effects of microdosing. Initial scientific investigations of microdosing are just beginning [8–11] (Rosenbaum D, Weissman C, Hapke E, Hui K, Petranker R, Dinh-Williams L-A, et al.: Microdosing psychedelic substances: demographics, psychiatric comorbidities, and comorbid substance use, in preparation) and future directions remain unclear.
While full-dose psychedelic research is growing in prominence and outcomes from full-dose studies can certainly inform microdosing studies, focusing solely on known full-dose outcomes could result in missing unanticipated benefits and challenges specific to microdosing. As such, beginning with an open, exploratory approach could result in a better understanding of the potential benefits and challenges specific to microdosing.
The present study aims to provide a data-driven taxonomy describing the positive and negative experiences reported by microdosers from an open-ended analysis of microdosing-specific outcomes, summarizing high-potential avenues for focused experimental investigations.
The benefits of full-dose psychedelics
Despite continued prohibition, modern research has revealed the promising potential of LSD and psilocybin for treating alcohol and tobacco dependence [14–17], depression [18, 19], and end-of-life anxiety [20–22], while related research on 3,4-methylenedioxymethamphetamine (MDMA) has shown great promise for treating post-traumatic stress disorder .
Psychedelics can also increase openness and occasion mystical-type experiences in healthy controls [24–26]. As full-dose psychedelics appear to aide in the relief of severe, chronic psychiatric conditions (e.g. depression, anxiety, PTSD), milder mental health concerns may plausibly be treated by lower, recurring doses.
This is especially worth considering if certain full-dose outcomes are found to rely on purely pharmacologic mechanisms rather than primarily on phenomenological experiences .
Limiting microdosing research to topics that have been investigated in full-dose research could prematurely overlook unpredicted and potentially distinct microdosing outcomes. Full-dose research has employed various focal assessments of symptomatology, mood, and personality that are likely applicable to microdosing research, but due to the low doses and lack of perceptual alteration intended in microdosing, other full-dose phenomena, such as ego dissolution and mystical-type experiences, are less relevant to microdosing research.
Instead, as a means of preparing for a broad range of outcomes, the present work solicited open-ended reports of benefits and challenges. Additionally, as psychedelic substances act on distinct yet overlapping neural receptor sites, it seems plausible that distinct patterns could emerge for different substances. The present study thus included microdosers who used LSD, psilocybin, or both.
The challenges of full-dose psychedelics
While psychedelics appear to have considerable potential benefits and low physiological risks [28–30], full-dose experiences can put participants under considerable psychological risk . In a survey targeting participants that had at least one challenging experience (“bad trip”) with psilocybin mushrooms, 39% of respondents rated their full-dose experiences as among the top 5 most psychologically difficult/challenging experiences of their lives .
Griffiths et al.  used both “high” (22 mg/70 kg) and “low” (1 or 3 mg/70 kg) doses of psilocybin as experimental and control conditions, respectively. A dose-response effect could be seen such that in the high-dose condition, 32% of participants reported physiological discomfort whereas only 12% reported the same in the low-dose condition; likewise, 26% reported anxiety in the high-dose condition versus 15% in the low-dose condition . Delayed-onset headaches are another possible side-effect of full-dose psilocybin .
To mitigate these risks, Johnson et al.  proposed safety guidelines for use with full-dose psychedelic substances, which rely on managing participant inclusion and having a comfortable, guided clinical setting.
As microdosing does not involve the intensity of experience present in full-dose research, challenging experiences may be less likely. One may, however, anticipate that less frequent, less intense versions of full-dose challenges could be present even at the very low doses used in microdosing (e.g. restlessness instead of insomnia, mild anxiety instead of fear, mild headaches).
As the study of microdosing is in its infancy, we could also expect there to be challenges that fall beyond the scope of reports based on full doses; the present study thus preferred open-ended surveying of drawbacks over pre-existing focal questionnaires.