Prevalence and Reasons for Microdosing Cannabis, Psilocybin, LSD, and MDMA Among US Adults

Abstract

Introduction:

Microdosing involves consuming low doses of psychoactive substances, typically 1/5th to 1/20th of a recreational dose. Despite increasing public attention to cannabis and psychedelics amid evolving drug policies, epidemiological data on microdosing remain limited.

Methods:

A cross-sectional, web-based survey (Characterizing the Epidemiology of Cannabidiol Use Survey) of 1,525 US adults was conducted in October-November 2023 and analyzed in 2024-2025 using Ipsos KnowledgePanel. Participants reported lifetime microdosing of cannabis, psilocybin, lysergic acid diethylamide (LSD), and 3,4-Methylenedioxymethamphetamine (MDMA). Lifetime prevalence, frequency, and reasons for microdosing were assessed, along with associations with demographics, mental health, quality of life, and cannabis and psychedelic policy environments. Survey weights were applied to generate nationally representative estimates.

Results:

Cannabis was the most commonly microdosed substance (9.4%; 95% CI=8.0, 10.7; 24.1 million adults), followed by psilocybin (5.3%; 95% CI=4.3, 6.3; 13.7 million adults), LSD (4.8%; 95% CI=3.8, 5.9; 12.4 million adults), and MDMA (2.2%; 95% CI=1.5, 2.9; 5.7 million adults). Cannabis (41.2%; 95% CI=33.3, 49.5) was primarily microdosed for medical purposes (e.g., “to manage pain”), while psilocybin (66.6%; 95% CI=56.9, 75.1), LSD (59.2%; 95% CI=46.5, 70.8) and MDMA (86.0%; 95% CI=68.8, 94.5) were more commonly microdosed for recreational purposes (e.g., “to get less high”). Across all substances, lifetime microdose use was more prevalent among respondents reporting poorer mental health and among those residing in jurisdictions permitting recreational cannabis use and decriminalized psychedelic possession.

Conclusions:

Despite remaining illegal at the federal level, a considerable number of US adults reported microdosing cannabis, psilocybin, LSD, and MDMA in their lifetime. Microdosing was associated with poorer mental health and was more common among respondents who lived in environments with fewer restrictions on the use of cannabis and psychedelics. As policy reforms continue to expand, microdosing prevalence may increase, making ongoing surveillance essential for evidence-based public health responses.

INTRODUCTION

Microdosing involves consuming low doses of psychoactive substances—typically 1/5th to 1/20th of a recreational dose¹—with the goal of avoiding the intense psychotropic effects of larger doses while providing subtle benefits such as improved mood, enhanced creativity, and reduced anxiety.² The practice of microdosing began as a therapeutic regimen focused on “classic psychedelics,” like psilocybin mushrooms or lysergic acid diethylamide (LSD),^1,3 but has since expanded to include other substances like cannabis, particularly low-dose tetrahydrocannabinol (THC) products, and “empathogens,” like 3,4-methylenedioxymethamphetamine (MDMA).^4–8 Despite anecdotal claims of benefits, clinical evidence for microdosing remains limited and contradictory, with few placebo-controlled randomized trials conducted in clinical populations and some evidence suggesting these benefits may stem from expectancy effects.^9–12 Microdosing classical psychedelics also raises safety concerns, including adverse effects such as anxiety, insomnia, and hallucinations,^11,13,14 alongside theoretical risks of valvular heart disease from chronic serotonin receptor activation.^15,16 Additional risks stem from the unregulated nature of many of these substances, including use of adulterated products or dosing errors,^17–19 particularly given that most individuals who microdose do not test their substances.^14,20

As microdosing has grown as a cultural phenomenon,²¹ many factors may have played a part in driving public interest, including an evolving cannabis and psychedelic policy landscape and the growing legitimacy of psychedelics as therapeutics for mental health conditions.^3,18,22 In the United States (US), the past decade has witnessed widespread cannabis legalization, with medical and recreational cannabis use permitted in most states, establishing legal markets for psychoactive substances.²³ Concurrently, a “psychedelic renaissance” has emerged, marked by FDA breakthrough designations for psilocybin for treatment-resistant depression and MDMA for post-traumatic stress disorder (PTSD), alongside growing state and local psychedelic decriminalization initiatives.^24,25 Mental health factors also appear central to microdosing, as prior research has identified mental health improvement, cognitive enhancement, and general well-being as the most commonly reported reasons for use, including for conditions such as depression, anxiety, ADHD, and chronic pain.^{3,8,13,14,20,22,26–30}

Despite this growing cultural phenomenon and changing legal landscape, critical evidence gaps persist. To date, the authors are aware of only one other population-based study that has examined microdosing prevalence in the US, reporting that approximately 3.7% of US adults microdosed psilocybin, LSD, or MDMA in the past year.³¹ However, this study did not examine cannabis microdosing, lifetime prevalence, reasons for use, or variations across policy environments and demographic groups. Beyond this, existing research has been confined to convenience samples that limit generalizability to the broader US population.^3,8,32–34 For instance, Cameron et al.⁸ found 13% lifetime microdosing prevalence among 2,200 participants recruited through snowball sampling via social media and online forums, while Harlow et al.³⁴ found 3.1% prevalence among young adults in Southern California. Internationally, population-based data are similarly sparse, with one nationally representative study from Germany estimating 2.7% lifetime prevalence for microdosing any psychedelic.³⁵ Additionally, cannabis microdosing has been particularly understudied despite the substance’s widespread legal availability and distinct therapeutic applications.^4,5,36 Understanding these patterns at the population level is critical to help clinicians and policymakers navigate the rapidly changing regulatory landscape for cannabis and psychedelic substances.

To address these gaps, this study reports on findings from a nationally representative survey examining lifetime and current microdosing, frequency of microdosing, and reasons for microdosing cannabis, psilocybin, LSD, and MDMA among US adults. Microdosing prevalence was also assessed across demographic characteristics, mental health status, quality of life, and policy environments to characterize the populations engaging in these behaviors. Investigating these factors is critical for identifying health disparities in use, informing clinical screening protocols, and tailoring harm reduction strategies to the groups most likely to use these substances.

METHODS

Study Sample

This study is part of a larger survey, the Characterizing the Epidemiology of Cannabidiol Use Survey,^37–39 which primarily collected data on behaviors related to cannabidiol (CBD) and other substances. Between October 25 and November 3, 2023, a cross-sectional, web-based survey was fielded using the Ipsos KnowledgePanel, ⁴⁰ a probability-based online panel recruited via address-based sampling covering approximately 97% of US households, including cell-phone-only households and those without internet access. KnowledgePanel members reside in all 50 US states and Washington, DC, and have been surveyed to provide nationally representative estimates of substance use.^{37–39,41,42} Survey invitations do not disclose the topic, minimizing selection bias related to the topic of interest.

For this study, Ipsos recruited a random sample of 4,505 KnowledgePanel members aged 18+ years to complete the survey in English or Spanish. Of these, 2,880 completed a screening questionnaire (63.9% completion rate) based on a predetermined target sample of n=1,000 people who have ever used CBD and n=500 people who have never used CBD. The target sample was designed to oversample CBD users to ensure adequate precision for the primary study aims examining CBD use behaviors with <±3% margin of error, with microdosing assessed as a secondary aim. To produce nationally representative estimates, study-specific poststratification weights were constructed that separately benchmarked CBD users and non-users to their respective population distributions and weighted the two subgroups in their proper proportion (see online Appendix). This oversampling and weighting strategy is a standard and well-documented design feature of Ipsos KnowledgePanel survey research.^43–45 Of the 2,880 respondents who completed the screening questionnaire, 1,525 respondents were eligible and completed the larger survey (53.0% qualification rate). The final sample size for the two groups were n=1,008 who have ever used CBD and n=515 who have never used CBD. The median completion time was 10 minutes, and participants received points redeemable for cash or merchandise and were entered into a KnowledgePanel sweepstakes. The UC San Diego Institutional Review Board deemed this study minimal risk human subjects research (45 CFR 46.104).

Measures

Before answering substance-specific questions, respondents were shown the following definition: “Microdosing refers to when someone consumes a very small amount of a psychedelic. By a small amount, this is usually about 1/5 to 1/20 of a recreational dose. The most common psychedelics that are microdosed are THC-containing cannabis, lysergic acid diethylamide (LSD), also known as ‘acid’, psilocybin-containing mushrooms, also known as ‘magic mushrooms’ or ‘shrooms”, and MDMA, also known as ‘Molly’ or ‘Ecstasy’.”

Participants were then asked about lifetime use for each substance using thresholds aligned with commonly cited microdosing ranges in the literature and online communities.^1,12,46–48 For cannabis: “Have you ever, even once, intentionally taken a ‘microdose’ of cannabis that contained THC? This would usually be an amount of about 2 milligrams of THC or less.” For psilocybin: “Have you ever, even once, taken a microdose of psilocybin-containing mushrooms, also known as ‘magic mushrooms’ or ‘shrooms’? This would be an amount of about 0.5 g or less.” For LSD: “Have you ever, even once, taken a microdose of LSD, also called ‘acid’? This would be an amount of about 1/5 of a normal dose/tablet or less.” For MDMA: “Have you ever, even once, taken a microdose of MDMA, also known as ‘Molly’ or ‘ecstasy’? This would be an amount of about 1/5 of a normal dose/tablet or less.” A “yes” response indicated lifetime microdosing for that specific substance.

Participants who reported lifetime microdosing were asked about frequency (“How many times have you microdosed [substance] in your entire life?”) with response options: “1 time,” “2 to 10 times,” “11 to 20 times,” “21 to 50 times,” “51 to 99 times,” or “100 or more times.” They were also asked about current use (“Do you now microdose [substance]?”) with response options: “every day,” “some days,” or “not at all,” modeled after the Behavioral Risk Factor Surveillance System (BRFSS) approach of assessing current smoking status.⁴⁹ For analyses, frequency responses were consolidated into 1-10 times, 11-50 times, and 51+ times, and “current use” was categorized as “every day” or “some days” versus “not at all.”

Individuals who reported lifetime microdosing were also asked to describe their primary reasons for doing so in an open-text format: “For what reasons or purpose did you microdose [substance]? Please explain in about 2-3 sentences.” Three independent annotators (K.Y., N.S., and W.K.) coded responses into four mutually exclusive categories: medical only (use for treating or managing health conditions), recreational only (use for enjoyment, curiosity, creativity, or social purposes), both (responses indicating both medical and recreational reasons), or other/unknown (insufficient detail to categorize or unclear reasons). Interrater reliability was high (Cohen’s κ≥0.85), with discrepancies resolved by consensus.

Jurisdiction of residence was classified using respondents’ approximate latitude and longitude derived from geocoded residential addresses provided by Ipsos. These were then mapped to state or local cannabis and psychedelic regulations following a previously described categorization schema.²¹ Policy classifications included: 1) all cannabis/psychedelic use restricted (prohibited or criminalized), 2) only medical cannabis permitted (no recreational cannabis or psychedelic decriminalization), 3) medical and recreational cannabis permitted (no psychedelic decriminalization), and 4) medical and recreational cannabis permitted plus psychedelic decriminalization at state or local levels.

Sociodemographic variables included gender (self-reported as male or female gender identity), age group (18-29, 30-44, 45-59, ≥60 years), race/ethnicity (non-Hispanic White, non-Hispanic Black, Hispanic, non-Hispanic other including ≥2 races), education (<high school/high school graduate, some college, college degree or higher), and metropolitan statistical area status (metro vs non-metro). Participants also self-rated their mental health and quality of life on 5-point scales (excellent, very good, good, fair, poor), which are single-item measures that have been formally validated with demonstrated construct validity in prior research and are widely used in national health surveys.^50,51

Statistical Analysis

To produce population-based estimates, this study used study-specific poststratification weights constructed by Ipsos that accounted for the oversampling of people who used CBD in the study design, demographic characteristics of the qualified sample, and survey nonresponse (see online Appendix). Weighted percentages and corresponding 95% CIs were calculated for each substance’s microdosing prevalence and stated reasons for use. Chi-square or Wald F-tests were used to assess significant differences across demographic groups or policy categories (P<0.05). Missing data represented less than 1% of values for all variables and were excluded via pairwise deletion. Analyses were conducted using the ‘survey’ package in R version 4.3.1 (R Foundation for Statistical Computing, Vienna, Austria.) to account for the complex sampling design.⁵² This study followed the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) guidelines for cross-sectional studies.

RESULTS

The analysis included data from 1,525 US adults who completed the survey. Lifetime microdosing prevalence was 9.4% (95% CI=8.0, 10.7) for cannabis, 5.3% (95% CI=4.3, 6.3) for psilocybin, 4.8% (95% CI=3.8, 5.9) for LSD, and 2.2% (95% CI=1.5, 2.9) for MDMA (Table 1). These prevalence rates correspond to an estimated 24.1 million (95% CI=20.5, 27.4 million) US adults for cannabis, 13.7 million (95% CI=11.1, 16.3 million) for psilocybin, 12.4 million (95% CI=9.8, 15.2 million) for LSD, and 5.7 million (95% CI=3.9, 7.6 million) for MDMA. Additionally, 3.3% (95% CI=2.5, 4.0) of adults reported current (every day or some days) cannabis microdosing, 1.0% (95% CI=0.6, 1.4) for psilocybin, 0.6% (95% CI=0.2, 0.9) for LSD, and 0.3% (95% CI=0.1, 0.5) for MDMA. Most adults who reported having ever used a microdose had done so infrequently (1-10 times) across all substances, though 2.2% (95% CI=1.6, 2.9) of US adults reported using a microdose of cannabis more than 50 times in their lifetime.

Table 1.

Prevalence and use patterns of cannabis, psilocybin, LSD, and MDMA microdosing among US adults

Substance	Prevalence		Frequency of Microdosing (Lifetime)
	Lifetime Prevalence Weighted % (95% CI)	Current Use Weighted % (95% CI)	1-10 times Weighted % (95% CI)	11-50 times Weighted % (95% CI)	51 or greater Weighted % (95% CI)
Cannabis	9.4 (8.0-10.7)	3.3 (2.5-4.0)	4.3 (3.3-5.3)	1.5 (1.0-1.9)	2.2 (1.6-2.9)
Psilocybin	5.3 (4.3-6.3)	1.0 (0.6-1.4)	3.8 (3.0-4.6)	1.0 (0.6-1.4)	0.4 (0.1-0.6)
LSD	4.8 (3.8-5.9)	0.6 (0.2-0.9)	3.2 (2.3-4.1)	1.0 (0.5-1.5)	0.4 (0.2-0.7)
MDMA	2.2 (1.5-2.9)	0.3 (0.1-0.5)	1.3 (0.7-1.9)	0.5 (0.3-0.9)	0.2 (0.0-0.4)

CI, confidence interval; LSD, lysergic acid diethylamide; MDMA, 3,4-methylenedioxymethamphetamine

Table 2 presents associations between demographic characteristics, health status, substance use policies, and lifetime microdosing by substance. Lifetime cannabis microdosing was more prevalent among adults aged 30-44 years (14.0%; 95% CI=11.0, 17.7) and those with some college education (12.7%; 95% CI=9.9, 16.1). Lifetime psilocybin microdosing was more common among males (6.4%; 95% CI=5.0, 8.2) than females (4.3%; 95% CI=3.3, 5.7). Microdosing prevalence was higher among those with ‘poor’ self-reported mental health (20.9%; 95% CI=13.2, 31.6) compared to those reporting ‘excellent’ mental health (7.9%; 95% CI=5.1, 12.1) for cannabis (p=0.003). This pattern was also observed for psilocybin (14.4%; 95% CI=7.8, 25.1 vs 4.7%; 95% CI=2.9, 7.7; p=0.011) and MDMA (7.5%; 95% CI=2.6, 19.6 vs 1.5%; 95% CI=0.5, 4.4; p=0.006). Similarly, respondents reporting ‘poor’ quality of life had higher microdosing prevalence compared with those reporting ‘excellent’ quality of life for cannabis (14.1%; 95% CI=6.5, 28.0 vs 11.3%; 95% CI=7.6, 16.6; p=0.012) and MDMA (4.7%; 95% CI=1.3, 15.2 vs 2.3%; 95% CI=0.9, 5.5; p=0.001). The prevalence of psilocybin microdosing was higher among adults in jurisdictions that had decriminalized psychedelic use (16.4%; 95% CI=9.7, 26.3) compared with those in states that prohibited all cannabis and psychedelic use (4.3%; 95% CI=3.0, 6.2; p<0.001). This pattern was also observed for LSD (9.2%; 95% CI=5.0, 16.3 vs 2.9%; 95% CI=1.8, 4.8; p=0.022), MDMA (6.2%; 95% CI=2.9, 12.6 vs 2.8%; 95% CI=1.5, 5.0; p=0.023) and to a lesser extent cannabis (13.9%; 95% CI=8.3, 22.2 vs 8.3%; 95% CI=6.2, 11.0; p=0.378).

Table 2.

Characteristics of lifetime cannabis, psilocybin, LSD and MDMA microdosing among US adults

Characteristic	Sample n	Cannabis		Psilocybin		LSD		MDMA
		Weighted % (95% CI)	P-value	Weighted % (95% CI)	P-value	Weighted % (95% CI)	P-value	Weighted % (95% CI)	P-value
Gender
Male	747	8.8 (7.1-10.8)	0.406	6.4 (5.0-8.2)	0.036	5.5 (4.1-7.1)	0.269	2.3 (1.5-3.5)	0.831
Female	776	10.0 (8.0-12.3)		4.3 (3.3-5.7)		4.2 (3.0-6.0)		2.2 (1.4-3.5)
Age Group
18-29	227	8.6 (5.8-12.6)	0.001	5.4 (3.4-8.4)	0.257	5.7 (3.2-10.0)	0.404	2.4 (1.2-4.7)	0.266
30-44	382	14.0 (11.0-17.7)		6.9 (4.9-9.6)		3.5 (2.2-5.4)		3.4 (2.2-5.2)
45-59	377	8.5 (6.0-11.8)		5.0 (3.4-7.2)		4.8 (3.1-7.4)		1.9 (0.9-3.8)
60+	537	6.8 (5.2-8.9)		4.3 (3.1-5.9)		5.4 (3.8-7.6)		1.5 (0.6-3.5)
Race/Ethnicity
Non-Hispanic White	1,082	9.8 (8.2-11.7)	0.591	6.2 (5.1-7.7)	0.145	5.0 (3.9-6.4)	0.879	2.3 (1.6-3.4)	0.962
Non-Hispanic Black	148	8.6 (5.4-13.6)		3.4 (1.7-6.6)		4.1 (2.0-8.4)		2.6 (1.0-6.5)
Hispanic	183	9.8 (6.5-14.7)		4.0 (2.3-6.7)		4.2 (2.4-7.0)		1.9 (0.9-4.1)
Non-Hispanic Other	110	6.7 (3.8-11.6)		4.1 (1.9-8.6)		5.6 (2.0-14.4)		2.0 (0.6-6.6)
Education
<High school or High school graduate	488	8.8 (6.9-11.2)	0.018	5.8 (4.3-7.8)	0.412	6.2 (4.5-8.4)	0.161	3.0 (1.9-4.9)	0.237
Some college	433	12.7 (9.9-16.1)		5.8 (4.2-8.0)		4.6 (3.1-6.7)		1.8 (1.0-3.1)
College or greater	602	7.5 (5.6-10.0)		4.4 (3.2-6.2)		3.6 (2.2-5.8)		1.8 (1.0-3.0)
MSA Status
Metro	1,313	9.1 (7.7-10.7)	0.328	5.3 (4.3-6.4)	0.855	4.6 (3.6-5.8)	0.34	2.1 (1.5-3.0)	0.458
Non-metro	210	11.2 (7.6-16.4)		5.6 (3.3-9.1)		6.2 (3.5-10.7)		3.0 (1.3-6.9)
Self-Reported Mental Health
Excellent	239	7.9 (5.1-12.1)	0.003	4.7 (2.9-7.7)	0.011	5.2 (2.6-10.0)	0.109	1.5 (0.5-4.4)	0.006
Very Good	478	7.5 (5.5-10.0)		5.0 (3.6-7.0)		4.6 (3.2-6.4)		1.1 (0.6-2.2)
Good	437	9.2 (7.1-12.0)		4.2 (2.9-6.0)		3.5 (2.2-5.6)		2.1 (1.2-3.6)
Fair	274	12.2 (8.8-16.7)		6.5 (4.4-9.6)		6.1 (3.9-9.5)		4.1 (2.4-6.9)
Poor	78	20.9 (13.2-31.6)		14.4 (7.8-25.1)		10.1 (5.2-18.6)		7.5 (2.6-19.6)
Self-Reported Quality of Life
Excellent	217	11.3 (7.6-16.6)	0.012	5.2 (3.1-8.4)	0.092	6.0 (3.3-10.9)	0.06	2.3 (0.9-5.5)	0.001
Very Good	595	6.4 (4.9-8.5)		4.3 (3.1-5.8)		4.3 (3.0-6.1)		0.8 (0.4-1.6)
Good	471	11.2 (8.7-14.4)		5.5 (4.0-7.5)		3.5 (2.3-5.3)		2.7 (1.5-4.6)
Fair	186	12.0 (8.4-16.9)		7.9 (4.8-12.6)		8.7 (5.4-13.7)		5.6 (3.1-10.0)
Poor	38	14.1 (6.5-28.0)		11.9 (5.0-25.6)		5.4 (1.5-17.5)		4.7 (1.3-15.2)
Cannabis and Psychedelic Policies
All cannabis and psychedelic use restricted	428	8.3 (6.2-11.0)	0.378	4.3 (3.0-6.2)	0.001	2.9 (1.8-4.8)	0.022	2.8 (1.5-5.0)	0.023
Medical cannabis use permitted	329	9.2 (6.6-12.7)		4.9 (3.2-7.5)		6.4 (4.2-9.6)		2.6 (1.5-4.4)
Medical and recreational cannabis use permitted	680	9.7 (7.7-12.1)		5.0 (3.8-6.6)		4.9 (3.4-6.8)		1.4 (0.7-2.5)
Medical and recreational cannabis use permitted and psychedelic use decriminalized	86	13.9 (8.3-22.2)		16.4 (9.7-26.3)		9.2 (5.0-16.3)		6.2 (2.9-12.6)

Note: Boldface indicates statistical significance (p<005).

CI, confidence interval; LSD, lysergic acid diethylamide; MDMA, 3,4-methylenedioxymethamphetamine; MSA, metropolitan statistical area.

Figure 1 presents reasons for lifetime microdosing by substance. Cannabis microdosing was more frequently reported for medical reasons only (41.2%; 95% CI=33.3, 49.5) (e.g., anxiety, depression, chronic pain), whereas psilocybin (66.6%; 95% CI=56.9, 75.1), LSD (59.2%; 95% CI=46.5, 70.8), and MDMA (86.0%; 95% CI=68.8, 94.5) were predominantly reported for recreational reasons only (e.g., “to get less high,” “to see how it felt”). Microdosing psilocybin, LSD, or MDMA for medical reasons only was less common, ranging from 5.1% for MDMA to 19.9% for psilocybin.

Figure 1.

Reasons for lifetime microdosing by substance among US adults, 2023

LSD, lysergic acid diethylamide; MDMA, 3,4-methylenedioxymethamphetamine. Unweighted sample sizes for lifetime microdose use: Cannabis n=230, Psilocybin n=140, LSD n=112, MDMA n=51. Error bars represent upper 95% confidence intervals. Medical only = microdosing for medical reasons only (e.g., “anxiety, depression, PTSD,” “chronic pain,” “insomnia”); Recreational only = microdosing for recreational reasons only (e.g., “to get high,” “to see how it felt”); Both = microdosing for both medical and recreational reasons (e.g., “for fun, for mental health resets, for creativity and productivity”); Other/Unknown = respondents who reported other reasons or did not specify (e.g., “no real reason,” “I was a teenager”).

DISCUSSION

This cross-sectional study provides nationally representative evidence that a substantial proportion of US adults have microdosed cannabis, psilocybin, LSD, or MDMA. Respondents more frequently reported recreational reasons for microdosing (e.g., to get less high) than medicinal (e.g., to help with anxiety). Across all substances, microdosing was more common among respondents with poorer mental health status and those living in jurisdictions with more permissive cannabis or psychedelic laws. These prevalence estimates align with a 2026 RAND Corporation report, which established a past-year psychedelic microdosing prevalence of 3.7%;³¹ the slightly higher lifetime estimates in this study (e.g., 5.3% for psilocybin) are consistent with this recent past-year benchmark. These rates are also generally consistent with estimates derived from previous convenience samples in the US,^8,34 though higher than the 2.7% lifetime prevalence for psychedelic microdosing reported in the only nationally representative international study conducted in Germany.³⁵ However, direct comparison is limited as prior studies consolidated psychedelics and did not specifically address cannabis microdosing. Observed differences may reflect differences in survey measures, sampling approach, geographic coverage, age distributions, or data collection timing.

Although microdosing has primarily been characterized as a treatment protocol using psilocybin and LSD,^2,10 this study found that cannabis microdosing was substantially more common among US adults. Lifetime cannabis microdosing (9.4%) exceeded psilocybin (5.3%), LSD (4.8%), and MDMA (2.2%), with current microdosing similarly more common for cannabis than psilocybin, LSD, and MDMA. Unlike the other substances, cannabis microdosing was more frequently used for medical purposes such as anxiety, depression, and chronic pain, potentially reflecting public perceptions of cannabis’ therapeutic potential and growing legal acceptance for medical use.^4,36,53 Additionally, unlike psilocybin, LSD, and MDMA, cannabis microdosing did not vary significantly across policy environments, possibly reflecting cannabis’ broad availability and reduced stigma from widespread legalization compared to psychedelics, which remain criminalized in most jurisdictions. These findings suggest that microdosing research and policy discussions should give equal attention to cannabis rather than focusing solely on psychedelics.

Psilocybin, LSD, and MDMA microdosing was more prevalent in jurisdictions with more permissive cannabis and psychedelic laws compared with jurisdictions where all use remained restricted. This association may reflect broader acceptance, reduced stigma, greater access, or a greater willingness to disclose use in permissive environments.^18,54,55 Notably, these differences emerged even though the manufacturing and sale of these substances remains illegal at both the state and federal level, suggesting that decriminalization of possession alone may be sufficient to influence use behaviors. However, given the cross-sectional design and lifetime assessment of microdosing, causal directionality cannot be established; it is equally plausible that jurisdictions with more prevalent microdosing are more likely to adopt permissive policies rather than policies driving use. Time-trend data examining microdosing patterns before and after such policy changes would be needed to establish temporal relationships. As additional states and municipalities decriminalize psychedelics,²⁵ microdosing will likely become more common, making ongoing surveillance essential for evidence-based policy development.

The predominantly recreational reasons for psilocybin, LSD, and MDMA microdosing suggests the concept has evolved beyond a therapeutic protocol to also encompass “dose titration,” reflecting the preference of individuals who microdose for controlled, low-intensity experiences that avoid the intense psychological effects associated with higher doses.^3,32,46 Still, a notable minority reported microdosing for medical purposes, consistent with anecdotal evidence of microdosing for conditions such as depression, anxiety, and ADHD.^13,26,30,32 Combined with the higher prevalence among those reporting poorer mental health and quality of life, these patterns support the potential that individuals may be self-medicating,^3,56,57 though the cross-sectional nature of this study precludes determining whether respondents are self-medicating, whether microdosing influences mental health outcomes, or whether shared factors explain both.⁵⁸ Further research, including longitudinal studies and randomized trials, is needed to clarify the safety and therapeutic value of microdosing. Future studies should also consider incorporating validated multi-item instruments such as the Patient Health Questionnaire-9 (PHQ-9), Generalized Anxiety Disorder-7 (GAD-7), and Short Form Health Survey-36 (SF-36) for more precise characterization of these mental health and quality of life associations.

Limitations

Several limitations should be considered. First, no standardized definition or validated measure for microdosing currently exists; this study addressed this gap by providing a quantitative definition, though this approach remains subject to self-reported dosing recall and interpretation. Second, participants were not asked about the temporal pattern or duration of use, limiting interpretation of these behaviors as “microdosing” in the traditional sense of a repeated protocol. Third, the open-text format for reasons for microdosing may have captured primary reasons rather than an exhaustive list, potentially underrepresenting the “both” category. Fourth, the cross-sectional design precludes establishing temporality and therefore limits causal inference, including for policy associations, as lifetime behaviors may have preceded recent policy reforms. Fifth, social desirability bias may have led to underreporting, though the anonymous survey design may have mitigated this. Sixth, the low prevalence of psilocybin, LSD, and MDMA microdosing resulted in small sample sizes for some subgroup analyses. Seventh, while poststratification weights accounted for CBD oversampling, residual bias from the CBD-enriched sampling frame cannot be fully excluded. For instance, since CBD is typically used for medical purposes,³⁹ the higher proportion of medical reasons for cannabis microdosing may be somewhat inflated despite weighting adjustments and should be interpreted with caution. Finally, the analyses were descriptive and bivariate in nature given the study’s primary aims, though confounders may explain certain observed associations. Future research would benefit from multivariable approaches to clarify independent predictors of microdosing and structured checklists to more accurately categorize reasons for use.

Conclusions

Microdosing has become a noteworthy public health phenomenon, with a substantial proportion of US adults reporting lifetime microdosing of cannabis, psilocybin, LSD, or MDMA. The higher prevalence in permissive policy jurisdictions suggests use may increase as more states implement policy reforms. These findings, combined with associations between poorer mental health and microdosing, provide essential baseline data for policymakers developing regulatory frameworks and underscore the need for standardized definitions and validated instruments for ongoing surveillance. Future research should include longitudinal studies examining temporal relationships between microdosing and mental health, as well as policy research evaluating how regulatory frameworks influence use and health outcomes.

Data Sharing Statement:

Data and documentation can be made available upon a reasonable request by emailing the corresponding author.