Psychopharmacology
January 2, 2019
Thomas Anderson, Rotem Petranker, Daniel Rosenbaum et al.
171 citations
People who currently or formerly microdosed psychedelics like LSD or psilocybin reported lower dysfunctional attitudes and negative emotionality, and higher wisdom, open-mindedness, and creativity compared to non-microdosers. These differences were observed in an online observational study using self-report questionnaires and a creativity task. The findings suggest potential benefits of microdosing, but controlled experiments are needed to confirm safety and clinical efficacy.
Harm Reduction Journal
July 9, 2019
Thomas Anderson, Rotem Petranker, Adam Christopher et al.
130 citations
A mixed-methods study of an active microdosing community categorizes the experiences participants report, identifying high-potential avenues for future scientific research. The resulting taxonomy distills intervention targets from participant reports to help allocate research funding efficiently. Microdosing research complements full-dose psychedelic studies as clinical treatments and neuropharmacological mechanisms are developed. The framework aims to guide researchers and clinicians as experimental microdosing research begins in earnest.
Journal of Psychopharmacology
February 28, 2020
Daniel Rosenbaum, Cory R. Weissman, Thomas Anderson et al.
75 citations
People who microdose psychedelics—taking small, non-hallucinogenic amounts of LSD or psilocybin—are less likely to report a history of substance use disorders or anxiety disorders than non-microdosers, but more likely to report recent recreational substance use. Among 909 participants recruited from Reddit, most microdosers used LSD (59.3%) or psilocybin (25.9%) on a one-day-on, two-days-off schedule. The findings suggest that microdosers differ from non-microdosers in psychiatric and substance-use profiles, and well-designed randomized controlled trials are needed to evaluate safety and potential benefits in clinical populations.
Frontiers in Psychology
July 10, 2020
Rotem Petranker, Thomas Anderson, Norman Farb
66 citations
Psychedelic research is experiencing a resurgence after decades of prohibition, driven by dissatisfaction with conventional mental health care and pioneering work by organizations like MAPS. Positive media coverage and commercial interests have accelerated hype, creating risks of conflicts of interest and lowered scientific standards. To avoid a replication crisis similar to those in psychology and medicine, researchers must adopt rigorous, transparent methods from Open Science: preregistration, open materials and data, reporting constraints on generality, and encouraging replication. The paper provides a pragmatic checklist and discusses how higher standards can build a trustworthy psychedelic science as these substances re-enter research and society.
Journal of Psychopharmacology
October 8, 2020
Rotem Petranker, Thomas Anderson, Larissa J. Maier et al.
57 citations
In a large online survey of 6,753 people who had microdosed psychedelics in the past year, most reported enhanced mood, creativity, focus, and sociability, and the most common challenge was 'None'. Contrary to expectations, having an approach-intention—microdosing to achieve a specific goal—predicted fewer rather than more benefits. Most participants did not test their substances. The perceived benefits greatly outweighed the challenges, but double-blind, placebo-controlled experiments are needed to confirm these self-reported effects.
Frontiers in Psychiatry
February 5, 2024
Rotem Petranker, Thomas Anderson, Youval Aberman et al.
14 citations
Microdosing, the practice of taking small, sub-hallucinogenic doses of psychedelics, has become popular, with users reporting benefits like improved mood and creativity. A review of 15 papers published before March 2022 critically analyzed the research practices in this field. The review concludes that it is premature to draw any conclusions about the efficacy or safety of microdosing because the quality of the research is not confirmatory. The authors propose potential causes for this state of the literature and offer suggestions for improvement.
April 12, 2020
Rotem Petranker, Thomas Anderson, Larissa J. Maier et al.
14 citations
preprint
A large survey of 6,753 people who microdosed LSD or psilocybin at least once in the past year found that the most commonly reported benefits were enhanced mood, creativity, focus, and sociability, partially replicating earlier findings. Most participants reported no challenges from microdosing, and the majority did not test their substances for purity. Contrary to expectations, microdosing with the intention of approaching a desired goal predicted fewer rather than more benefits. The authors conclude that the reported benefits outweigh the challenges, but emphasize that double-blind, placebo-controlled experiments are needed to confirm these self-reported effects.
November 1, 2018
Thomas Anderson, Rotem Petranker, Daniel M. Rosenbaum et al.
11 citations
preprint
People who regularly consume small amounts of psychedelics like LSD or psilocybin—a practice called microdosing—report lower levels of dysfunctional attitudes and negative emotionality, and higher levels of wisdom, open-mindedness, and creativity compared to those who do not microdose. This pre-registered study, the first to investigate microdosing and mental health, recruited participants from online forums. Although promising, the findings are preliminary and warrant controlled experimental research to test safety and clinical efficacy. Microdosing may offer clinical benefits without the hallucinogenic effects of full-dose psychedelic therapy.
May 26, 2020
Rotem Petranker, Juensung J. Kim, Thomas Anderson
4 citations
preprint
People who microdose psychedelics like LSD or magic mushrooms do so mainly for clinical reasons and to boost productivity, but often struggle with unknown optimal dosing. Outcomes vary widely, from strong endorsement to disappointment at no effect. The analysis of 118 survey responses identified four themes: reasons, practice, outcomes, and meta-commentary, which included warnings against overexcitement. The findings suggest that even low doses may provide a sense of meaning lacking in Western culture, likely through enhanced psychological flexibility and connectedness, though placebo-controlled experiments are needed to confirm.
Cureus
May 1, 2024
Zach Hart, Thomas Anderson, Hanna Fanous et al.
2 citations
A 64-year-old woman with hypothyroidism and parotid sarcoidosis developed acute chest pain and shortness of breath after receiving a ketamine infusion for mental health treatment. Echocardiography showed a temporarily reduced ejection fraction and apical hypokinesis, and angiography found no blocked coronary arteries, consistent with stress-induced cardiomyopathy. The timing suggests ketamine may have triggered the cardiomyopathy. Ketamine is increasingly used for depression and substance use disorders, but caution is warranted in patients with cardiovascular disease, and more research on its cardiac effects is needed.
BJPsych Open
February 16, 2026
Zeina Beidas, Anya Ragnhildstveit, Adam Blackman et al.
1 citation
This is a protocol for a phase II trial testing whether very low doses of psilocybin (2 mg, a microdose) can safely and effectively treat major depressive disorder. Forty adults with MDD will receive either psilocybin or a placebo once weekly for four weeks, then all will receive psilocybin for another four weeks. The trial will measure changes in depression symptoms, mood, well-being, attention, creativity, mindfulness, and pro-sociality. Results will be published regardless of outcome. The findings are expected to guide future research on dose regimens, effect sizes, and the role of expectancy bias, and to inform debates about sub-threshold versus threshold doses of psilocybin.
BJPsych Open
May 13, 2026
Zeina Beidas, Anya Ragnhildstveit, Adam Blackman et al.
This is a correction notice for a previously published study protocol. The original protocol describes a phase II double-blind placebo-controlled randomised partial crossover trial investigating microdosing psilocybin for major depressive disorder. No new findings or data are presented.
Research Square
February 23, 2026
Rotem Petranker, Norman Farb, Omer A. Syed et al.
Repeated low doses of psilocybin were safe and well tolerated in adults with major depressive disorder but did not show greater antidepressant effects than placebo. In a randomized, double-blind trial, 39 participants received either 2 mg psilocybin or placebo weekly for four weeks. Both groups reported similar reductions in depression scores on the PHQ-9 (psilocybin: -5.4; placebo: -6.0) and other measures. The microdose-first group showed slightly more improvement on a dysfunctional attitudes scale than the placebo-first group. No serious adverse events occurred, and symptom reductions continued during an open-label phase. Trial participation itself contributed to clinically meaningful improvement.
November 16, 2025
Zeina Beidas, Anya Ragnhildstveit, Adam Blackman et al.
preprint
A phase II trial will test whether microdosing psilocybin (2 mg weekly) outperforms placebo for major depressive disorder. Forty adults will receive either psilocybin or placebo for four weeks, then all will receive psilocybin for another four weeks. Depression symptoms and other measures will be assessed at baseline, after four weeks, and after eight weeks, with follow-ups for two years. The study aims to clarify whether microdosing has genuine antidepressant effects or whether benefits are due to expectancy, and to inform future dose regimens and the therapeutic role of sub-threshold versus threshold doses.
Journal of Humanistic Psychology
February 14, 2022
Rotem Petranker, Juensung Kim, Thomas Anderson
People who microdose psychedelics report four main themes: reasons for doing it, the practice itself, outcomes, and meta-commentary. Even at low doses, psychedelics may provide a sense of meaning, and reported benefits appear to occur regardless of motivation, likely due to enhanced psychological flexibility and connectedness. Double-blind, placebo-controlled experiments are needed to substantiate these reports.