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The emerging science of microdosing: A systematic review of research on low dose psychedelics (1955 – 2021)

Vince Polito, Paul Liknaitzky

December 15, 2021 preprint DOI: 10.31234/osf.io/edhqz (opens in new tab)

Study at a glance

AI-extracted from the abstract
Characteristics Systematic review
Sample size 44
Population Participants in microdosing studies from 1955 to 2021
Topics Microdosing
Keywords Expectancy theory Mood Cognition Perception Mental health Clinical psychology Applied psychology Psychotherapist
Citations 2
Key findings Microdosing research shows changes in pain perception, time perception, conscious state, neurophysiology, cognitive processing, and mental health, and the review argues that expectancy effects do not fully explain these findings.

Abstract

The use of low doses of psychedelic substances (microdosing) is attracting increasing interest. This systematic review summarises all empirical microdosing research to date, including a set of infrequently cited studies that took place prior to prohibition. Specifically, we reviewed 44 studies published between 1955 and 2021, and summarised reported effects across six categories: mood and mental health; wellbeing and attitude; cognition and creativity; personality; changes in conscious state; and neurobiology and physiology. Studies showed a wide range in risk of bias, depending on design, age, and other study characteristics. Laboratory studies found changes in pain perception, time perception, conscious state, and neurophysiology. Self-report studies found changes in cognitive processing and mental health. We review data related to expectation and placebo effects, but argue that claims that microdosing effects are largely due to expectancy are premature and possibly wrong. In addition, we attempt to clarify definitional inconsistencies in the microdosing literature by providing suggested dose ranges across different substances. Finally, we provide specific design suggestions to facilitate more rigorous future research.

Comparable studies

Other systematic reviews and meta-analyses on microdosing, most cited first.

Study Year Design Participants
The emerging science of microdosing: A systematic review of research on low dose psychedelics (1955–2021) and recommendations for the field Human participants in microdosing studies 2022 Systematic review n = 44
The utility of microdosing over the past 5 years Drugs with published comparisons of microdose and therapeutic dose pharmacokinetics 2008 Systematic review n = 18
The therapeutic potential of microdosing psychedelics in depression Healthy volunteers and patient samples 2020 Systematic review
Potential safety, benefits, and influence of the placebo effect in microdosing psychedelic drugs: A systematic review 2020 Systematic review
Microdosing Psychedelics: Current Evidence From Controlled Studies. Healthy adults 2024 Systematic review

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