The Viability of Microdosing Psychedelics as a Strategy to Enhance Cognition and Well-being - An Early Review

Interest in psychedelic substances has resurged for both therapeutic and recreational purposes, yet rigorous research remains limited because of legal restrictions and stigma. Earlier studies suggest full-dose psychedelic experiences can produce therapeutic benefits for conditions such as substance dependence, end-of-life anxiety, depression and OCD, and recreational use has been associated with increased openness, prosocial behaviour, positive affect and creative problem-solving. At the same time, full-dose experiences can be challenging and, in rare cases, lead to persistent adverse outcomes such as panic attacks, flashbacks and hallucinogen persisting perception disorder (HPPD). Microdosing, commonly defined in the paper as ingesting between one tenth and one twentieth of a typical psychedelic dose so that effects are subperceptual, has been proposed as a way to capture some benefits while reducing risks associated with full-dose use. Bornemann sets out to summarise the extant literature on psychedelic microdosing to evaluate whether it is a viable strategy to enhance cognition and well-being and to identify potential risks. The review places qualitative and quantitative evidence on a spectrum of evidential strength and aims to clarify where more rigorous research is needed.

Bornemann conducted searches in Scopus, PubMed, ProQuest, Google Scholar and an additional search engine using the terms: microdosing AND (psychedelics OR lsd OR psilocybin OR mdma OR dmt OR mescaline OR psychoactive). The initial search was performed on 11 May 2019 and was amended on 12 November 2019, with further ad hoc searches to locate full-dose psychedelic studies that included microdose control conditions. Inclusion criteria required studies to report novel results, be published in scientific venues, and involve human microdosing effects; review articles, popular-press pieces and animal studies were excluded. Titles and abstracts were screened for relevance, and 21 documents met inclusion criteria and were read in full. The final corpus comprised eleven observational studies, one quasi-experimental study, and nine experimental studies. Bornemann notes that much of the existing evidence is qualitative and structures the review subsections in order of increasing evidential strength, indicating which cited studies are qualitative versus quantitative. An overview table is referenced in the text but is not present in the extracted material.

General effects: Early observational and qualitative reports commonly describe microdosing days as pleasant, with one self-study protocol (no sample size provided) reporting roughly 80% of narrative accounts as positive or neutral. An online questionnaire administered to psychedelic-focused forums (n = 1116) found about one fifth of respondents who reported microdosing also reported negative effects, described as mainly psychological and acute. Interview-based and forum-analysing qualitative studies generally reported mostly positive experiences—particularly improvements in depression and anxiety for some respondents—alongside reports of challenges such as accidental overdosing, concerns about long-term consequences and problems related to illegality and stigma (for example, measuring doses, hiding the practice, and uncertain substance purity). One study of college students reported that almost 69% of past-year microdosers indicated at least one negative consequence, with hallucinations reported by 44.2%, though the paper notes these may reflect dosing errors rather than microdosing per se. Creativity: Several qualitative analyses, including a content analysis of Reddit posts, found frequent self-reports of enhanced creativity. Quantitatively, one online questionnaire study reported higher creativity scores among current and former microdosers relative to non-microdosers, though directionality is unclear. The single quasi-experimental study assessed festival attendees on measures of divergent and convergent thinking and reported significant improvements on both tasks under an estimated microdose of psychedelic truffles, while fluid intelligence did not change; this study lacked a placebo control and laboratory conditions. By contrast, other experimental work has reported null results: a double-blind, placebo-controlled study of LSD in 20 volunteers (0, 6, 13, 26 μg) found no robust creative performance differences except a marginal change at the highest dose (which produced noticeable subjective effects and hence may not be a true microdose), and at least one observational study and other experimental trials reported no significant creativity changes. Overall, evidence on creativity is mixed. Focus and productivity: Anecdotal and qualitative reports, drawn from interviews, forum analyses and questionnaires, commonly describe increased productivity, better focus and reduced procrastination among microdosers, though some accounts report impaired focus. One longitudinal observational study that collected daily e-mails (n = 98) and follow-up questionnaires (n = 63) reported reduced distractibility and increased absorption at a 6-week follow-up, offering some systematic evidence for longer-term effects. Experimental placebo-controlled studies have generally been null for working memory, focus and productivity, apart from marginal increases in vigour at higher doses that may exceed microdose ranges. Studies administering multiple low doses of LSD (placebo, 5, 10, 20 μg) to older adults showed minimal cognitive effects and dose-related increases in vigilance reduction, dizziness and sleepiness; confinement to bed during administration was noted as a possible confound. Time perception studies yielded inconsistent results: one LSD microdose study found overestimation of supra-second intervals in the 2000–4000 ms range, whereas other research with psilocybin microdoses reported increased instability of internal time representation. Mood and general well-being: Qualitative accounts frequently describe elevated mood, increased energy, greater openness and improved social relations. Quantitative cross-sectional work reported lower dysfunctional attitudes, reduced negative emotionality and increased measures such as wisdom and open-mindedness among current and former microdosers compared with non-microdosers, though causality is uncertain. One longitudinal study reported decreases in stress at 6 weeks but also increases in neuroticism in some participants. Two higher-dose clinical studies that included low-dose arms provided mixed information: a low-dose psilocybin condition was attributed some positive behaviour and mood changes at 6 months but lacked a placebo; another psilocybin study with a full placebo arm observed slight drowsiness, greater sensitivity and intensification of pre-existing mood states in the lowest dose (45 μg/kg, N = 8) amidst mostly null mood findings. Qualitative reports also indicated decreased use of substances such as caffeine, alcohol and tobacco, and preliminary qualitative evidence suggested improvements in OCD, PTSD and narcolepsy. A quantitative online sample (N = 410) rated microdosing as more effective than conventional treatments for conditions such as ADD/ADHD and anxiety disorders in their self-report comparisons. An experimental psilocybin microdose study reported some OCD symptom improvement without a placebo control and without dose-condition differences, raising expectancy concerns. Depression: Several qualitative self-report studies suggested anti-depressive effects. In clinical research on cancer patients that compared high and low psilocybin doses, 32% of patients who received the low dose met a clinical response criterion for depression (defined as 50% reduction from baseline), although the low-dose effect was much smaller than the full-dose effect. Anxiety: Findings for anxiety are inconsistent. Qualitative reports include both relief from social anxiety and increases in anxiety; one survey found 35% of past-year microdosers reported at least one episode of increased anxiety. When asked directly, 59.2% of respondents in one study reported that microdosing had helped with anxiety. Quantitatively, a low-dose arm in cancer-patient psilocybin research showed a 24% clinical response rate for anxiety but also that 15% experienced an anxiety episode during the session. A small study using 20 μg of LSD as a control condition (low-dose) reported slight increases in state and trait anxiety, but the low-dose sample was very small (n = 4). Overall, the net effect of microdosing on anxiety remains unclear. Physiological effects: Most physiological data are qualitative. Reports about tolerance are mixed, with some users reporting buildup and others not; ingestion a few times per week did not seem to produce substantial tolerance in one qualitative account. Some participants reported reductions in migraine frequency, supported by qualitative reports of subhallucinogenic doses used for chronic migraine and cluster headache relief; a quantitative survey found participants rated microdosing as more effective than conventional options for such nervous system conditions. Conversely, qualitative and some experimental reports noted insomnia, increased heart rate, headaches, nausea and general physiological discomfort. Mild headaches were observed in an LSD microdose experimental study, and a full-dose study with a low-dose arm reported physiological discomfort in 12% of patients in the low-dose condition. No systematic long-term physiological studies were reported; the paper flags cardiovascular safety (noting that LSD and psilocybin are 5-HT2B agonists potentially implicated in valvular heart disease) as a future research priority.

Bornemann interprets the body of evidence as indicating a variety of potential benefits of microdosing, including improvements in mood, focus and creativity, while acknowledging that some people report no benefits or selective negative outcomes such as increased anxiety. The discussion highlights substantial methodological limitations across the literature: many studies use convenience samples that are likely biased, qualitative and cross-sectional designs that limit causal inference, small sample sizes in experimental arms, lack of placebo controls in several investigations and the near absence of long-term follow-up data. One consequence of sampling bias is potential underrepresentation of people who tried microdosing and stopped because of negative or absent effects. Placebo effects are discussed as a significant unresolved issue. Two arguments against a purely placebo explanation are noted: one study reported specific patterns of dosing and effects that the authors judged unlikely to arise solely from expectancy, and another found no association between participants' stated expectations and their reported effects. Conversely, other investigators observed that many reported advantages were also described as disadvantages by different participants, consistent with strong expectancy or contextual influences; the paper also notes that individual genetic and epigenetic differences might account for heterogeneity in responses. Considering the placebo-controlled work so far, Bornemann observes a trend that more rigorous studies yield more modest or null results. Questions about mechanisms and dose equivalence are raised. Although microdoses use the same active substances as full doses and therefore may engage similar receptor systems, reported phenomenology and tolerance patterns do not necessarily mirror full-dose effects. The paper suggests neuroimaging studies—such as investigations of default-mode network (DMN) effects—could clarify whether microdoses produce brain changes analogous to those hypothesised for therapeutic full-dose administrations. A further concern is inconsistency in the operational definition of a microdose: experimental studies reviewed define very low psilocybin doses across a wide range (for example, 12 μg/kg to 45 μg/kg), and some higher 'low-dose' conditions produce perceptual effects that violate subperceptual definitions. Bornemann recommends standardised experimental procedures to resolve dose-range ambiguities and to identify a dose that maximises putative benefits while remaining subperceptual. Finally, practical barriers to strong research—legal restrictions, stigma and the high cost of legally acquiring substances—are emphasised, and the author concludes that although preliminary findings are promising, caution is warranted and future work should prioritise double-blind, placebo-controlled experimental paradigms and longitudinal studies.