Psychedelic Microdosing Research Articles

LSDDEP2: study protocol for a randomised, double-dummy, triple-blind, active placebo-controlled, parallel groups trial of LSD microdosing in patients with major depressive disorder

BackgroundMajor depressive disorder (MDD) poses a significant global health burden with available treatments limited by inconsistent efficacy and notable side effects. Classic psychedelics, including lysergic acid diethylamide (LSD), have garnered attention for their potential in treating psychiatric disorders. Microdosing, the repeated consumption of sub-hallucinogenic doses of psychedelics, has emerged as a self-treatment approach for depression within lay communities. Building upon preliminary evidence and the successful completion of an open-label pilot trial of microdosing LSD for depression (LSDDEP1), this protocol outlines a phase 2b randomised controlled trial (LSDDEP2). The main objective of LSDDEP2 is to assess the modification of depressive symptoms, measured by the Montgomery–Åsberg Depression Rating Scale (MADRS), following a regimen of LSD microdoses versus placebo.MethodsThis is a randomised, double-dummy, triple-blind, active placebo-controlled, parallel groups trial of LSD microdosing in patients meeting DSM-5 criteria for major depressive disorder. Participants will undergo an 8-week LSD microdosing regimen using the titratable MB-22001 formulation taking two doses a week. All doses will be self-administered at home and will be titratable from 4 to 20 μg based on subjective perception and tolerability. In addition to depression symptoms, outcome will include psychiatric and personality inventories, sleep and activity tracking, electroencephalography (EEG), blood biomarkers, semi-structured interviews, and safety (e.g. adverse event, laboratory exam) measures.DiscussionThis study will be the first randomised controlled trial to administer controlled microdoses of LSD for treatment of MDD in participants’ naturalistic environment. The measures included are designed to assess the drug’s safety, mechanism, and treatment efficacy over placebo in this population. The results of this study will be important for assessing the viability of psychedelic microdosing as an additional treatment option and for informing the direction of future clinical trials.Trial registrationANZCTR, ACTRN12624000128594. Prospectively Registered on 13 February 2024.

Is microdosing a placebo? A rapid review of low-dose LSD and psilocybin research.

Some recent research and commentary have suggested that most or all the effects reported by people who microdose psychedelics may be explained by expectations or placebo effects. In this rapid review, we aimed to evaluate the strength of evidence for a placebo explanation of the reported effects of microdosing. We conducted a PubMed search for all studies investigating psychedelic microdosing with controlled doses and a placebo comparator. We identified 19 placebo-controlled microdosing studies and summarised all positive and null findings across this literature. Risk of bias was assessed using the Cochrane risk-of-bias tool for randomised trials. The reviewed papers indicated that microdosing with LSD and psilocybin leads to changes in neurobiology, physiology, subjective experience, affect, and cognition relative to placebo. We evaluate methodological gaps and challenges in microdosing research and suggest eight reasons why current claims that microdosing is predominately a placebo are premature and possibly wrong: (1) there have been only a small number of controlled studies; (2) studies have had small sample sizes; (3) there is evidence of dose-dependent effects; (4) studies have only investigated the effects of a small number of doses; (5) the doses investigated may have been too small; (6) studies have looked only at non-clinical populations; (7) studies so far have been susceptible to selection bias; and (8) the measured impact of expectancy is small. Considering the available evidence, we conclude that it is not yet possible to determine whether microdosing is a placebo.

State Cannabis and Psychedelic Legislation and Microdosing Interest in the US

ImportanceDespite growing interest in psychedelics, there is a lack of routine population-based surveillance of psychedelic microdosing (taking “subperceptual” doses of psychedelics, approximately one-twentieth to one-fifth of a full dose, over prolonged periods). Analyzing Google search queries can provide insights into public interest and help address this gap.ObjectiveTo analyze trends in public interest in microdosing in the US through Google search queries and assess their association with cannabis and psychedelic legislative reforms.Design, Setting, and ParticipantsIn this cross-sectional study, a dynamic event-time difference-in-difference time series analysis was used to assess the impact of cannabis and psychedelic legislation on microdosing search rates from January 1, 2010, to December 31, 2023. Google search rates mentioning “microdosing,” “micro dosing,” “microdose,” or “micro dose” within the US and across US states were measured in aggregate.ExposureEnactment of (1) local psychedelic decriminalization laws; (2) legalization of psychedelic-assisted therapy and statewide psychedelic decriminalization; (3) statewide medical cannabis use laws; (4) statewide recreational cannabis use laws; and (5) all cannabis and psychedelic use restricted.Main Outcome and MeasuresMicrodosing searches per 10 million Google queries were measured, examining annual and monthly changes in search rates across the US, including frequency and nature of related searches.ResultsSearches for microdosing in the US remained stable until 2014, then increased annually thereafter, with a cumulative increase by a factor of 13.4 from 2015 to 2023 (7.9 per 10 million to 105.6 per 10 million searches, respectively). In 2023, there were 3.0 million microdosing searches in the US. Analysis at the state level revealed that local psychedelic decriminalization laws were associated with an increase in search rates by 22.4 per 10 million (95% CI, 7.5-37.2), statewide psychedelic therapeutic legalization and decriminalization were associated with an increase in search rates by 28.9 per 10 million (95% CI, 16.5-41.2), statewide recreational cannabis laws were associated with an increase in search rates by 40.9 per 10 million (95% CI, 28.6-53.3), and statewide medical cannabis laws were associated with an increase in search rates by 11.5 per 10 million (95% CI, 6.0-16.9). From August through December 2023, 27.0% of the variation in monthly microdosing search rates between states was explained by differences in cannabis and psychedelics legal status.Conclusion and RelevanceThis cross-sectional study found that state-led legislative reforms on cannabis and psychedelics were associated with increased public interest in microdosing psychedelics.

PAM trial protocol: a randomised feasibility study of psychedelic microdosing–assisted meaning-centred psychotherapy in advanced stage cancer patients

BackgroundAn advanced cancer diagnosis can be associated with a significant profile of distress. Psychedelic compounds have shown clinically significant effects in the treatment of psychological distress in patients with advanced-stage cancer. Given the challenges of delivering timely and effective intervention in the advanced cancer context, it is possible that an alternative, more pragmatic, approach lies in psychedelic ‘microdosing’. Microdosing refers to repeated administration of psychedelics in sub-hallucinogenic doses. The purpose of this study is to evaluate the feasibility of conducting a full-scale randomised controlled trial comparing psychedelic microdose-assisted–meaning-centred psychotherapy (PA-MCP) to standard meaning-centred psychotherapy (MCP) in New Zealand indigenous (Māori) and non-indigenous people with advanced cancer and symptoms of anxiety and/or depression. Although MCP is a well-established psychotherapeutic treatment in advanced cancer populations, the potential efficacy and effectiveness of this therapy when delivered alongside a standardised microdose regimen of a psychedelic compound have not been investigated.MethodsParticipants with advanced-stage cancer and symptoms of anxiety and/or depression (N = 40; 20 Māori, 20 non-Māori) will be randomised under double-blind conditions to receive 7 sessions of MCP alongside 13 doses of either an LSD microdose (4–20 µg) (PA–MCP) or inactive placebo (placebo-MCP). The feasibility, acceptability, and safety of this intervention and physiological and psychological measures will be recorded at baseline, at each session of MCP, and at a 1-month and 6-month follow-up.DiscussionOur findings will evaluate the feasibility, acceptability, and safety of a larger randomised controlled trial and provide an initial indication of the potential benefits of psychedelic microdosing for psychological distress in advanced-stage indigenous and non-indigenous cancer patients.Trial RegistrationNZCTR, ACTRN12623000478617. Registered 11 May 2023. https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=385810&isReview=true.

Psychedelic Microdosing among Young Adults from Southern California.

Despite common depictions in the media, there is little scientific evidence on microdosing psychedelic drugs. We assessed awareness, prevalence, and dosing practices of microdosing psychedelic drugs among young adults 18-22 years old from Southern California (2018-2019). We examined whether sociodemographic factors, personality traits, mental health, or other substance use behaviors were correlated with having ever microdosed. Among 2,396 participants, 293 (12%) had heard of microdosing and 74 (3%) ever microdosed. Among those who had heard of microdosing, 79% correctly defined microdosing as taking an amount of a psychedelic much lower than a standard dose, whereas 15% misperceived microdosing as a standard psychedelic dose. Psilocybin was the most common drug ever microdosed (70%), followed by lysergic acid diethylamide (LSD, 57%). Among those who ever microdosed, ~18% reported using psychoactive doses far higher than would be generally considered a microdose. White race, male/masculine gender identity, bisexual identity, past 6-month other drug use, greater attention deficit/hyperactivity disorder symptoms, mindfulness, and sensation-seeking were positively associated with having ever microdosed in multivariable models. Young adult microdosing merits further attention from scientific and public health professionals to help prevent misperceptions and potential adverse consequences as well as explore its potential therapeutic applications.

Effects of psychedelic microdosing versus conventional ADHD medication use on emotion regulation, empathy, and ADHD symptoms in adults with severe ADHD symptoms: A naturalistic prospective comparison study.

Adults with attention-deficit hyperactivity disorder (ADHD) often struggle with emotion regulation (ER), impacting their empathic skills and relationships. ADHD medication might not be as effective for ER issues as for ADHD symptoms. Microdosing (MD) psychedelics has shown promise for ADHD treatment and previous studies reported social-emotional benefits. Two online prospective studies investigated MD effects on ER and empathy in adults with severe ADHD symptoms across three assessments: baseline, two-, and four-week post-initiation. Study 1 examined adults initiating MD on their own (n = 233, n = 64, and n = 44) and found positive effects on ER (cognitive reappraisal and expressive suppression) and aspects of empathy (perspective-taking and personal distress). Study 2, including a control group and an ADHD symptom scale, compared individuals only MD (n = 180, n = 50, and n = 38) to individuals using conventional ADHD medication (n = 37, n = 27, and n = 28). After 4 weeks, ADHD symptoms were lower in the MD group. Only improvements in expressive suppression persisted after adding the control group. This study indicates the positive effects of MD psychedelics on ADHD symptoms and ER in adults with severe ADHD symptoms while lacking evidence for effects on empathy.

The risk of chronic psychedelic and MDMA microdosing for valvular heart disease.

Psychedelic microdosing is the practice of taking very low doses of psychedelic substances, typically over a longer period of time. The long-term safety of chronic microdosing is relatively uncharacterized, but valvular heart disease (VHD) has been proposed as a potential risk due to activation of the serotonin 5-HT2B receptor. However, this risk has not yet been comprehensively assessed. This analysis searched for all relevant in vitro, animal, and clinical studies related to the VHD risk of lysergic acid diethylamide (LSD), psilocybin, mescaline, N,N-dimethyltryptamine (DMT), and the non-psychedelic 3,4-methylenedioxymethamphetamine (MDMA). All five compounds and some metabolites could bind to the 5-HT2B receptor with potency equal to or greater than that of the 5-HT2A receptor, the primary target of psychedelics. All compounds were partial agonists at the 5-HT2B receptor with the exception of mescaline, which could not be adequately assessed due to low potency. Safety margins relative to the maximum plasma concentrations from typical microdoses were greater than known valvulopathogens, but not without potential risk. No animal or clinical studies appropriately designed to evaluate VHD risk were found for the four psychedelics. However, there is some clinical evidence that chronic ingestion of full doses of MDMA is associated with VHD. We conclude that VHD is a potential risk with chronic psychedelic microdosing, but further studies are necessary to better define this risk.

The difference between ‘placebo group’ and ‘placebo control’: a case study in psychedelic microdosing

In medical trials, ‘blinding’ ensures the equal distribution of expectancy effects between treatment arms in theory; however, blinding often fails in practice. We use computational modelling to show how weak blinding, combined with positive treatment expectancy, can lead to an uneven distribution of expectancy effects. We call this ‘activated expectancy bias’ (AEB) and show that AEB can inflate estimates of treatment effects and create false positive findings. To counteract AEB, we introduce the Correct Guess Rate Curve (CGRC), a statistical tool that can estimate the outcome of a perfectly blinded trial based on data from an imperfectly blinded trial. To demonstrate the impact of AEB and the utility of the CGRC on empirical data, we re-analyzed the ‘self-blinding psychedelic microdose trial’ dataset. Results suggest that observed placebo-microdose differences are susceptible to AEB and are at risk of being false positive findings, hence, we argue that microdosing can be understood as active placebo. These results highlight the important difference between ‘trials with a placebo-control group’, i.e., when a placebo control group is formally present, and ‘placebo-controlled trials’, where patients are genuinely blind. We also present a new blinding integrity assessment tool that is compatible with CGRC and recommend its adoption.

Psychedelic microdosing hits a rough patch in clinical trials.

Psychedelic microdosing hits a rough patch in clinical trials.

Turn On, Tune In, Drop Out? A Typology of Psychedelic Microdosing as Technologies of the Self

Psychedelic microdosing, or taking small doses of psychedelic substances that do not induce intoxication or altered states but rather subtle outcomes such as increased focus, has quickly become a mass media phenomenon. Many claim microdosing has become the new secret to enhancement in work contexts. Drawing from literature on psychedelic microdosing, technologies of the self, self-identity and the sociology of work and leisure, this study understands microdosing as a technology individuals introduce into their lives to modify themselves for various purposes. We explore the ways in which the 1960s iconic psychedelic drugs, that once offered turning on, tuning in and dropping out, are now finding new uses across different contexts. Taking a cultural-sociological perspective, we examine how individuals use microdoses of classic psychedelic drugs and how they make sense of microdosing in their daily lives. Based on our findings, we identify three different uses of psychedelic microdosing: (1) as technology of self-esteem and control at work, (2) as a self-help technology, and (3) as a technology of ‘slow living’.

Psilocybin microdosers demonstrate greater observed improvements in mood and mental health at one month relative to non-microdosing controls

Psilocybin microdosing involves repeated self-administration of mushrooms containing psilocybin at doses small enough to not impact regular functioning. Microdose practices are diverse and include combining psilocybin with substances such as lion’s mane mushrooms (Hericium erinaceus; HE) and niacin (vitamin-B3). Public uptake of microdosing has outpaced evidence, mandating further prospective research. Using a naturalistic, observational design, we followed psilocybin microdosers (n = 953) and non-microdosing comparators (n = 180) for approximately 30 days and identified small- to medium-sized improvements in mood and mental health that were generally consistent across gender, age and presence of mental health concerns, as we all as improvements in psychomotor performance that were specific to older adults. Supplementary analyses indicated that combining psilocybin with HE and B3 did not impact changes in mood and mental health. However, among older microdosers combining psilocybin, HE and B3 was associated with psychomotor improvements relative to psilocybin alone and psilocybin and HE. Our findings of mood and mental health improvements associated with psilocybin microdosing add to previous studies of psychedelic microdosing by using a comparator group and by examining the consistency of effects across age, gender, and mental health. Findings regarding the combination of psilocybin, HE and B3 are novel and highlight the need for further research to confirm and elucidate these apparent effects.

Psychedelic Microdosing, Mindfulness, and Anxiety: A Cross-Sectional Mediation Study

ABSTRACT While anecdotal reports claim that psychedelic microdosing reduces anxiety and mood symptoms, evidence supporting these claims is scarce. This cross-sectional study investigated the association between microdosing and trait anxiety. Furthermore, it was investigated if trait mindfulness mediated this association. Participants completed anonymous online questionnaires and were divided into three groups: current microdosers (n = 186), former microdosers (n = 77) and microdosing-naïve controls (n = 234). Trait anxiety and trait mindfulness were measured using the State-Trait Anxiety Inventory – Trait subscale (STAI-T) and the 15-item Five-Facet Mindfulness Questionnaire (FFMQ-15) respectively. Current and former microdosers reported lower STAI-T scores compared to microdosing-naïve controls. Furthermore, associations of current and former microdosing with trait anxiety were mediated by trait mindfulness, with small effects of FFMQ-15 Total, Non-judging and Non-reactivity scores. However, in an exploratory analysis, all associations between microdosing and STAI-T scores became non-significant when participants with previous macrodose experience (n = 386) were excluded. Our findings suggest that RCT<apos;>s are warranted to test causal hypotheses concerning the effects of microdosing and the role of trait mindfulness in the effects of microdosing, while controlling for previous macrodose experience.

Subject in the Making: Technologies of the Self and Aspirations for a Good Life in Contemporary Denmark

ABSTRACT Coping with crisis is fundamental for human life, but so is the pursuit of everything good and fruitful. We revisit Foucault’s technologies of the self as an analytical lens for what people do when pursuing a good life in contemporary Denmark. Comparing three emerging self-improvement domains; psychedelic micro-dosing, meditation and mindfulness, and fitness self-tracking, we explore processes though which individuals become subjects of their own actions. We argue that engaging in these transformational practices produces and reflects different notions of self, yet all involve attempts at managing vulnerabilities by accepting, controlling and balancing tensions between self-making and relation-making.

Asking questions of psychedelic microdosing.

A citizen science approach to research has shown that the improvements in mood and cognition associated with psychedelic microdosing are likely due to a placebo effect.

Self-blinding citizen science to explore psychedelic microdosing.

Microdosing is the practice of regularly using low doses of psychedelic drugs. Anecdotal reports suggest that microdosing enhances well-being and cognition; however, such accounts are potentially biased by the placebo effect. This study used a 'self-blinding' citizen science initiative, where participants were given online instructions on how to incorporate placebo control into their microdosing routine without clinical supervision. The study was completed by 191 participants, making it the largest placebo-controlled trial on psychedelics to-date. All psychological outcomes improved significantly from baseline to after the 4 weeks long dose period for the microdose group; however, the placebo group also improved and no significant between-groups differences were observed. Acute (emotional state, drug intensity, mood, energy, and creativity) and post-acute (anxiety) scales showed small, but significant microdose vs. placebo differences; however, these results can be explained by participants breaking blind. The findings suggest that anecdotal benefits of microdosing can be explained by the placebo effect.

A quantitative exploration of the relationships between regular yoga practice, microdosing psychedelics, wellbeing and personality variables

ABSTRACT Objective: The current study aimed to explore whether the subjective effects of microdosing psychedelics are comparable to those of yoga in relation to psychological wellbeing, depression, anxiety and stress. It also explored the relationship between yoga, microdosing and personality. Method: The sample comprised 339 participants, yoga (n = 131), microdose (n = 69), microdose and yoga (n = 54) and control (n = 85). All completed measures of personality (M5-50 and Tellegen Absorption Scale), mood (Depression, Anxiety and Stress Scale-21) and wellbeing (Ryff Scales of Psychological Wellbeing). Results: The yoga and microdosing groups scored significantly higher on psychological wellbeing and absorption than the control. The microdosing and yoga group had lower depression scores than the microdose only group, and lower anxiety scores than the yoga only group. Furthermore, the microdosing and yoga group had the highest absorption score. Openness was significantly lower in the control group than in all other groups. Conclusions: While we cannot infer that yoga and microdosing lead to increased wellbeing, openness and absorption, or to decreased depression and anxiety, the findings suggest that the subjective effects of microdosing psychedelics are comparable to those of yoga and that the combination of both might be beneficial. KEY POINTS What is already known about this topic: (1) Yoga often leads to improved psychological wellbeing, decreased depressive and anxiety symptoms, decreased neuroticism, and increased openness and absorption. (2) A small number of recent studies have found that taking subthreshold doses of psychedelic substances, known as microdosing, has improved psychological wellbeing, reduced depressive, anxiety and stress symptoms and increased the personality traits of openness and absorption. What this topic adds: (1) We are the first researchers to compare the effects of yoga with psychedelic microdosing on wellbeing and personality. (2) Our findings suggest the effects of microdosing psychedelic substances might be comparable to those of yoga. (3) Our study implies the combination of both yoga and microdosing has complementary effects on general wellbeing and absorption.

Positive expectations predict improved mental-health outcomes linked to psychedelic microdosing

Psychedelic microdosing describes the ingestion of near-threshold perceptible doses of classic psychedelic substances. Anecdotal reports and observational studies suggest that microdosing may promote positive mood and well-being, but recent placebo-controlled studies failed to find compelling evidence for this. The present study collected web-based mental health and related data using a prospective (before, during and after) design. Individuals planning a weekly microdosing regimen completed surveys at strategic timepoints, spanning a core four-week test period. Eighty-one participants completed the primary study endpoint. Results revealed increased self-reported psychological well-being, emotional stability and reductions in state anxiety and depressive symptoms at the four-week primary endpoint, plus increases in psychological resilience, social connectedness, agreeableness, nature relatedness and aspects of psychological flexibility. However, positive expectancy scores at baseline predicted subsequent improvements in well-being, suggestive of a significant placebo response. This study highlights a role for positive expectancy in predicting positive outcomes following psychedelic microdosing and cautions against zealous inferences on its putative therapeutic value.

Microdosing psychedelics: Demographics, practices, and psychiatric comorbidities.

Microdosing psychedelics - the practice of consuming small, sub-hallucinogenic doses of substances such as LSD or psilocybin - is gaining attention in popular media but remains poorly characterized. Contemporary studies of psychedelic microdosing have yet to report the basic psychiatric descriptors of psychedelic microdosers. To examine the practices and demographics of a population of psychedelic microdosers - including their psychiatric diagnoses, prescription medications, and recreational substance use patterns - to develop a foundation on which to conduct future clinical research. Participants (n = 909; Mage = 26.9, SD = 8.6; male = 83.2%; White/European = 79.1%) recruited primarily from the online forum Reddit completed an anonymous online survey. Respondents who reported using LSD, psilocybin, or both for microdosing were grouped and compared with non-microdosing respondents using exploratory odds ratio testing on demographic variables, rates of psychiatric diagnoses, and past-year recreational substance use. Of microdosers, most reported using LSD (59.3%; Mdose = 13 mcg, or 11.3% of one tab) or psilocybin (25.9%; Mdose = 0.3 g of dried psilocybin mushrooms) on a one-day-on, two-days-off schedule. Compared with non-microdosers, microdosers were significantly less likely to report a history of substance use disorders (SUDs; OR = 0.17 (95% CI: 0.05-0.56)) or anxiety disorders (OR = 0.61 (95% CI: 0.41-0.91)). Microdosers were also more likely to report recent recreational substance use compared with non-microdosers (OR = 5.2 (95% CI: 2.7-10.8)). Well-designed randomized controlled trials are needed to evaluate the safety and tolerability of this practice in clinical populations and to test claims about potential benefits.

Perceived outcomes of psychedelic microdosing as self-managed therapies for mental and substance use disorders.

The regular consumption of very small doses of psychedelic drugs (known as microdosing) has been a source of growing media and community attention in recent years. However, there is currently limited clinical and social research evidence on the potential role of microdosing as therapies for mental and substance use disorders. This paper examined subjective experiences of microdosing psychedelics to improve mental health or to cease or reduce substance use, and examined sociodemographic and other covariates of perceived improvements in mental health that individuals attributed to microdosing. An international online survey was conducted in 2018 and examined people's experiences of using psychedelics for self-reported therapeutic or enhancement purposes. This paper focuses on 1102 respondents who reported current or past experience of psychedelic microdosing. Twenty-one percent of respondents reported primarily microdosing as a therapy for depression, 7% for anxiety, 9% for other mental disorders and 2% for substance use cessation or reduction. Forty-four percent of respondents perceived that their mental health was "much better" as a consequence of microdosing. In a multivariate analysis, perceived improvements in mental health from microdosing were associated with a range of variables including gender, education, microdosing duration and motivations, and recent use of larger psychedelic doses. Given the promising findings of clinical trials of standard psychedelic doses as mental health therapies, clinical microdosing research is needed to determine its potential role in psychiatric treatment, and ongoing social research to better understand the use of microdosing as self-managed mental health and substance use therapies.

Psychedelic Microdosing: Prevalence and Subjective Effects

ABSTRACT Anecdotal reports suggest that the administration of sub-hallucinogenic doses of psychedelic compounds on a chronic, intermittent schedule – a practice known as psychedelic microdosing – is becoming increasingly popular among young adults due to its purported ability to reduce symptoms of depression and anxiety while improving cognitive function and promoting social interaction. Using an anonymous online survey, we collected data from 2347 people to 1) assess the prevalence of psychedelic microdosing and characterize the demographics of microdosers, 2) determine whether microdosers associate the practice with changes in mood, cognitive function, social interaction, or physiology, and 3) investigate frequent motives for discontinuing the practice. Fifty-nine percent of respondents (NT = 2183) reported familiarity with the concept of psychedelic microdosing, with 17% (383 respondents, NT = 2200) having engaged in this practice. Microdosers attributed psychedelic microdosing with improving their mood, decreasing their anxiety, and enhancing their memory, attention, and sociability. The most frequently cited reasons for quitting microdosing (NT = 243) were the risks associated with taking an illegal substance (24.28%) and the difficulty of obtaining psychedelic compounds (22.63%). Overall, our findings suggest that psychedelic microdosing is relatively common and is subjectively associated with a broad spectrum of socio-affective, cognitive, and physical outcomes.