Observing Microdosing:

Effects on Cognitive Performance and Mental Health


The integration of microdosing into regular daily routine has become prevalent in mainstream culture (Leonard, 2015). ‘Microdosing’ refers to the practice of taking of psychedelic substances (e.g. psilocybin or lysergic acid diethylamide; LSD) in small, sub-perceptual amounts on a regular basis (Fadiman, 2011). The specifics of dosage and dosage intervals remains largely undefined. For the purposes of this study, we are leaving it up to participants to define what microdosing means to them and collect this data to better inform future studies. At recreational doses, psychedelics have been associated with alterations in cognition, sensation, affect, and neurophysiology (Nichols, 2016). At microdoses, while the goal is not to feel acutely ‘high’, reported effects include more subtle increases in creativity, productivity, social ability, focus, analytical thinking, positive mood, memory, mindfulness, and general wellbeing (Anderson, 2019). Many also report using microdosing to self-medicate for intractable mental health issues including depression, anxiety, and ADHD (Gregoire, 2016). Some effects may be residual, meaning that they outlast the life of the psychedelic substance, and very few adverse events have been reported (Fadiman, 2017). The effects of microdosing on cognitive performance and mental health  remain largely unexplored. 

Anecdotal, subjective reports of microdosing are abundant in online blogs, podcasts, and books, as well as a few recently published studies (Johnstad, 2018; Prochazkova et al., 2018; Polito & Stevenson, 2019). However, there are limited published, peer-reviewed objective studies of the true effects of microdosing psychedelic substances. Regardless of whether microdosing is being used to treat a specific symptom or condition, or to generally enhance cognitive performance, personal growth, or creativity, given that a microdose is, by definition, sub-perceptual, it is difficult to truly evaluate potential benefits without using objective outcome measures.

The collection of objective outcome measures in large sample sizes has historically been challenging due to limited resources (e.g. study staff, funding, time). Quantified Citizen (QC) is an advanced data management platform that leverages mobile technology via mobile apps and the rapidly growing capacity to securely collect data through connected devices, allowing research participants to perform surveys and assessments on their own, without having to physically visit a scientific laboratory or clinic. This study will use a combination of quantitative and qualitative objective methods measured with the QC mobile app to explore the effects of microdosing on cognitive performance and mental health, in comparison to a non-microdosing group. 

Individuals who self-identify as microdosers of psychedelic substances and individuals who do not microdose will be invited to participate in this voluntary study. Psychedelics will not be provided as part of the study, nor will instructions on how to obtain or administer them. Rather, participants in the microdosing group will be individuals who are already familiar with the practice and would be microdosing regardless.

Once informed consent has been obtained, participants will be asked to complete an intake questionnaire (this will take approximately 10 minutes), including basic demographic information (age range, sex, level of education, employment status), basic medical history (major health concerns, mental health diagnoses, head injuries, neurological conditions, and pre-existing issues with visual acuity, color discrimination, hearing), and self-reported history of psychedelic use. They will then complete a baseline battery of self-administered cognitive performance and mental health assessments via the QC app (this will take approximately 20 minutes). This entire process will take approximately 30 minutes. 

After the baseline assessments have been completed, participants will be invited to complete brief daily questionnaires for the duration of their study involvement. These daily brief rating scales have been adapted from the Fadiman protocol (Fadiman, 2015), to mirror those used by Polito & Stevenson (2019), and will ask participants to rate their subjective experience of the previous day on feelings of connectedness, contemplation, creativity, focus, happiness, productivity, and well-being. A 5-point Likert scale will be used (from “much less than average” to “much more than average”). In addition, participants will be asked daily whether they have microdosed, taken any other substances or medications, and will provide a space for free text entry of any other observed effects. 

In addition to the daily questionnaires, all participants will be asked to complete the comprehensive battery of assessments (same as baseline) on a monthly basis. All digital data collection will be self-administered; participant identity will remain anonymous. The monthly battery of cognitive performance and mental health assessments (completed at baseline, after each month, and at the end of their study involvement) will include:

      Auditory perception threshold (dBHL tone audiometry using Hughson-Westlake method of determining hearing threshold) (Apple ResearchKit, 2018)

      Visual Acuity and Contrast Sensitivity (Landolt C methods) (Apple ResearchKit, 2018)

      Finger tapping performance (to assess basic motor capabilities/dysfunction such as speed, accuracy, and rhythm) (Apple ResearchKit, 2018)

      Spatial Memory (to assess visuospatial memory and executive function) (Apple ResearchKit, 2018)

      Paced Auditory Serial Addition Test (measures cognitive function that assesses auditory information processing speed, flexibility, and calculation ability) (Apple ResearchKit, 2018)

      Depression Anxiety Stress Scales (DASS-21) (Lovibond & Lovibond, 1995).


ResearchKit is an open source framework introduced by Apple. Using six of the already developed active tasks, we are going to ask participants to complete these four times throughout the study period, assuming they choose to participate for the entire 3 months (at the onset of their involvement, after the first month, after the second month, and at the end of their involvement).  This selection of active tasks was made in consultation with Dr. Jyoti Mishra, a neuroscientist from the Neural Engineering and Translation Labs at UC San Diego, with the underlying goal of quantifying cognitive performance using objective, valid, and reliable measures of sensory and cognitive processing. By measuring auditory perception threshold, visual acuity, contrast sensitivity, cognitive performance and motor capabilities, visuospatial memory, executive function, and cognitive function, we aim to observe cognitive performance and signs of cognitive plasticity over the 3-month period in both the microdosing and non-microdosing groups. Participants will also be asked to complete a monthly questionnaire that asks them to confirm that they still consent to participate in the study. Additionally, participants are asked again about their microdosing routine and invited to fill out the PANAS (1998). At the end of a participant’s study involvement they will be asked to complete a short study closing questionnaire that should take them no more than 5 minutes to complete.

Finally, participants will be provided with the option of allowing the Quantified Citizen app to access their Apple Health of Google Fit data. This is strictly optional and not required to participate in this study. Participants may turn this off at any time. Apple Health and Google Fit both track activity levels (step count, biking distance, sleep, etc., which may also contribute to differences in cognitive performance and mental health). This data will supplement the survey data to help observe any changes that occur over the study period. 

This study is intended to be broadly exploratory. The study variables and research designs were selected to tap into a number of variables that have been identified in prior research as being relevant to psychedelic use in particular (Polito & Stevenson, 2019). The primary focus is to observe whether microdosing is associated with objective, measurable changes in cognitive performance (basic auditory and visual processing, neuromuscular integrity via finger tapping) – as indicators of neurophysiological effects. Secondary aims are to observe and potentially replicate the findings of previously reported benefits (including daily subjective feelings and monthly assessments of mental health; Polito & Stevenson, 2019) and identify any potential side effects that occur during the study period. Results of this study will generate hypotheses for future, larger-scale experimental studies. In addition, an improved understanding of the effects of microdosing will ultimately lead to better safety and maximize potential benefits.




Leonard A. How LSD Microdosing Became the Hot New Business Trip. Rolling Stone. 20 Nov 2015.

Fadiman J. The psychedelic explorer’s guide: Safe, therapeutic, and sacred journeys. Simon and Schuster; 2011.

Anderson et al. Psychedelic microdosing benefits and challenges: an empirical codebook. 2019

Watson D. et al. Development and validation of brief measures of positive and negative affect: The PANAS Scales. Journal of Personality and Social Psychology, 1988.

Nichols D. Psychedelics. Pharmacol Rev. 2016; 68: 264–355.

Gregoire C. Everything You Wanted To Know About Microdosing (But Were Afraid To Ask). Huffington Post. 13 Jan 2016.

Fadiman J. Microdose Research: Without approvals, control groups, double-blinds, staff or funding by Dr James Fadiman. Psychedelic Press. 2017.

Johnstad PG. Powerful substances in tiny amounts: An interview study of psychedelic microdosing. Nordic Studies on Alcohol and Drugs. 2018; 35: 39–51.

  • Join the study: