Limitations
The constraints inherent to the study's design, sample, and data collection methods. These are real boundaries on what the eventual findings can claim about combat veterans, microdosed LSD, or PTSD more broadly.
Methodological scope
Limitations and delimitations.
The constraints that bound what the Microdosing Vets study can claim, and the scope choices that shape the research design. Documented as a methodological reference for prospective participants, committee reviewers, and researchers reading the recruitment materials.
The distinction
Two categories, two purposes.
Qualitative research methodology distinguishes between limitations — the constraints inherent to the design, sample, or data collection that bound the conclusions a study can support — and delimitations: the deliberate scope choices a researcher makes about what to include and what to leave out. Limitations describe what the study cannot do. Delimitations describe what the study chose not to do. Both shape what the eventual findings will and will not be able to say.
Delimitations
The deliberate choices that bound the study's scope: which population, which substance, which age range, which recruitment channels. Each choice excludes something the design could have included, with a reason.
Limitations
What constrains the study's conclusions.
Several methodological constraints bound what the eventual findings can claim. Each is named here so that committee reviewers, peer readers of the published work, and prospective participants understand the design's limits before they engage with it.
Sample composition
Recruitment relies on snowball sampling and online channels, which may not capture the full diversity of the combat veteran population living with PTSD. The resulting sample will likely skew toward veterans who are online, who are connected to networks that share research opportunities, and who are willing to disclose self-directed use of a Schedule I substance. The findings will accordingly be bounded in their generalizability.
Self-report
The study relies on participant self-report of microdosing practice, symptom experience, and perceived effects. Participants may not accurately recall their experiences. They may underreport or overreport depending on memory, mood at the time of interview, social-desirability pressures, or the emotional weight of revisiting their service-connected trauma.
Retrospective design and recall bias
The interview is retrospective: participants reflect on past experiences with microdosed LSD rather than reporting in real time. Recall bias is an unavoidable feature of that design. Methodological triangulation through the Friendly Observer interview may mitigate some of the distortion, but the Friendly Observer is not a neutral instrument either — they bring their own views of the participant's PTSD and of self-directed use of an illegal substance, and those views shape what they remember and choose to share.
No longitudinal follow-up
The study design does not include longitudinal follow-up with participants. The eventual findings will document experience as recalled in a single interview window. They will not be able to speak to the long-term sustainability of any reported effects, the trajectory of symptom change over time, or the durability of integration practices participants describe.
Ethical and legal context
The study examines self-directed use of a Schedule I substance. Confidentiality and de-identification protocols are in place and are described in the consent process, but the legal context surrounding microdosed LSD may still constrain how openly participants speak. The data the study can collect is the data participants are willing to disclose under those conditions.
Delimitations
The scope choices that shape the design.
Each delimitation below represents a choice the design makes about who is included, what substance is examined, and which channels recruitment runs through. Together they define the population and the practice the study sets out to document.
U.S. combat veterans only
The study population is limited to United States combat veterans. Veterans from other countries and civilians with PTSD are out of scope. The reason is methodological: the combat-veteran experience of trauma is shaped by a specific institutional, cultural, and operational context, and the qualitative analysis is bounded by that context. The findings will speak to this population and not beyond it.
Age range: 21–50
Participants must be over the age of 21, which ensures they are legally able to provide informed consent and that they bring a baseline of post-service life experience to the interview. The upper age cap of 50 excludes many older veterans who would otherwise meet eligibility criteria. The reason is recall: bounding the age range improves the likelihood that memories of microdosing practice, military service, and the period between them are accessible enough to support a substantive interview.
Single substance: microdosed LSD
The study focuses exclusively on microdosed LSD, despite acknowledging that veterans commonly microdose other substances — psilocybin most prominently. The exclusion is methodological rather than evaluative: the qualitative effects of different psychedelics are substance-specific, and pooling experiences across substances would obscure rather than clarify what microdosed LSD does for this population. A psilocybin-focused study is planned as a separate post-dissertation phase under the same investigator, pending its own ethics approval.
Prescription medications are not excluded
Participants who are taking prescribed antidepressants, anti-anxiety medications, or other psychiatric prescriptions are eligible. Their presence introduces some confounds into the qualitative description of microdosing effects. The reason the design includes them anyway: the published literature suggests that conventional first-line pharmacotherapy for combat-related PTSD is often insufficient on its own, and the experiences participants describe with microdosing alongside prescribed medication are part of the practice the study is trying to document.
Recruitment is online
Recruitment runs primarily through online channels and social-media platforms. Veterans who are not active online — for reasons of access, preference, or otherwise — are unlikely to encounter the recruitment materials and are therefore unlikely to enter the sample. This is an acknowledged constraint on representativeness, accepted because no remote qualitative study can fully resolve it.
Education: high school or equivalent
Participants must have completed at least a high school education or its equivalent. The threshold is set to support the cognitive and literacy demands of a long-form qualitative interview and the consent process that precedes it. The choice excludes veterans without formal education who may otherwise have relevant experiences with microdosing and PTSD; that exclusion is acknowledged here as a limit on the population the study can represent.
Read the rest of the study design.
The methodology, the ethics scaffold, the team behind it, and the research question this work sets out to answer.
About the study → The research team