01
Background
Contemporary psychedelic trials regularly combine drug administration with structured non-pharmacological procedures (SNP) across preparation, dosing, and post-dosing phases.
What are psychedelics?
Psychedelics include several classes of psychoactive compounds, such as tryptamines, ergolines, and phenethylamines. Common examples include psilocybin, LSD, DMT, and mescaline. These compounds may be naturally occurring or synthetic, and they are currently being investigated for their therapeutic potential in psychiatry.
For this project, what matters is not only the compound itself, but how it is studied in structured clinical trials. These contemporary psychedelic trials regularly combine drug administration with structured non-pharmacological procedures (SNP) across three phases of treatment: preparation phase, dosing phase, and post-dosing phase.
Kelmendi et al. (2022). Psychedelics. Current Biology, 32, R55–R71. ↗
More on SNP — definitions, vocabulary, and what the literature has noticed
1
What we mean by SNP
SNP (structured non-pharmacological procedures) are organized non-drug procedures surrounding psychedelic drug administration.
In many contemporary psychedelic trials, SNP are arranged around a three-phase structure:
Preparation phase
→
Dosing phase
→
Post-dosing phase
In practice, these phases are implemented through preparation sessions, one or more dosing sessions, and post-dosing sessions, as specified in the trial protocol.
Examples of SNP may include preparatory meetings, therapist or facilitator presence, safety monitoring, music, room arrangement, post-dosing discussion, and integration sessions. [1,2,3]
This terminology is intentionally neutral. It names when these procedures occur, without yet deciding whether they should be understood as psychological support, psychotherapy, safety monitoring, background conditions, or part of the intervention.
2
Not limited to "psychotherapy" trials
This SNP structure is not limited to studies explicitly described as psychedelic-assisted psychotherapy. Even trials that avoid the term psychotherapy often include a preparation phase, a dosing phase, and a post-dosing phase. [1,4]
3
An unstable vocabulary
The field uses overlapping terms for these structured non-pharmacological procedures: psychological support, psychotherapy, monitoring, psychosocial intervention, preparation, integration, set and setting, and therapeutic framework. These terms do not always pick out clearly distinct practices. [3,4,5]
4
What the literature has already noticed
Recent reviews and guidelines have called for clearer reporting of non-pharmacological and extra-pharmacological elements in psychedelic trials, including session number, duration, provider role, manuals, fidelity, setting, and therapeutic framework. [3,6]
5
The remaining issue
Clearer reporting is necessary, but it does not by itself settle how these procedures are understood within a trial. The same procedure may be described as support, psychotherapy, safety monitoring, risk minimization, or part of the intervention. [4,5,7]
Reporting asks: What was done?
Our next question: What was it taken to be?
02
The Puzzle
Across the literature, similar procedures are not always described in the same way. At first sight, this may seem like a terminological issue. But it is not yet clear that terminology alone captures what is at stake.
Unpack the puzzle
The same structured non-pharmacological procedures (SNP) may be described as psychological support, psychotherapy, monitoring, integration, safety management, or part of a therapeutic framework.
The puzzle is not only that different terms are used. It is that different terms may position the same procedure differently within a trial.
A procedure may be treated as:
- a background condition
- a safety procedure
- psychological support
- psychotherapy
- part of the intervention being tested
This raises the question:
When a psychedelic trial includes SNP, what role are those procedures taken to play within the trial?
The classificatory question: What is this procedure called?
Our question: What role is it taken to play within the trial?
We examine this puzzle through the Goodwin-Villiger disagreement over psilocybin trials.
03
Case: The Goodwin–Villiger Disagreement
The Goodwin-Villiger disagreement provides a case in which similar procedures within a broadly similar trial context are characterized differently.
Explore the case →
04
Our Proposal: Epistemic Perspectives
One way of clarifying this disagreement is to ask what epistemic perspective structures the trial. By epistemic perspectives, we do not mean merely different terminological choices or personal views. We mean background assumptions that shape: what counts as the intervention, what is causally primary, and what the trial is designed to test.
Explore the proposal →
05
Why This Matters
Different epistemic perspectives may lead researchers to treat similar procedures differently. This affects:
- How results are interpreted
- Which trials are seen as comparable
- How non-pharmacological procedures are reported
Take-Home Message
The disagreement is not only about the classification of structured non-pharmacological procedures (SNP). It also concerns how a SNP is framed within a trial and what epistemic role this SNP plays, given the underlying epistemic perspective of the trial.
03
Case: The Goodwin–Villiger Disagreement
The Goodwin–Villiger disagreement provides a case in which similar procedures within a broadly similar trial context are characterized differently.
Both Goodwin et al. (2023) and Villiger (2025) engage, directly or indirectly, with the COMP360 Trial, characterizing the role of its structured non-pharmacological procedures (SNP) differently.
COMP360 Trial Context
Randomized 1:1:1 psilocybin trial (25 mg / 10 mg / 1 mg)
Preparation phase
→
Dosing phase
→
Post-dosing phase
The relevant point for our purposes is that psilocybin administration is embedded in a structured sequence of non-pharmacological procedures. These procedures provide the shared object of discussion in the Goodwin–Villiger disagreement.
The relevant point for our purposes is that psilocybin administration is embedded in a structured sequence of non-pharmacological procedures. These procedures provide the shared object of discussion in the Goodwin–Villiger disagreement.
Interpreting the Same Trial Structure
The diagram fixes the shared trial structure. The comparison below shows how Goodwin et al. (2023) and Villiger (2025) assign different roles to the procedures organized within that structure.
- Discusses COMP360 directly
- Emphasizes support and safety
- Tends to separate psychological support from psychotherapy
- Discusses COMP360 indirectly, through Murphy et al. (2022)'s account
- Emphasizes psychotherapeutic embedding and therapeutic alliance
- Treats the surrounding procedures as psychotherapeutically significant
What the case shows — roles, the puzzle, and the question it raises
1
What the case shows
At first glance, the disagreement looks like a classificatory dispute: Is this psychotherapy, psychological support, monitoring, or safety management? But classification alone does not fully capture what is at stake.
The deeper issue is that the same procedure can be assigned different roles within the trial:
- as a background condition
- as a safety procedure
- as psychological support
- as psychotherapy
- as part of the intervention being tested
2
The question raised by the case
The Goodwin–Villiger disagreement, therefore, raises a more general question: when a psychedelic trial includes SNP, what role are those procedures taken to play within the trial?
Are they conditions that allow the drug-induced experience to occur safely? Or are they part of the causal process through which the treatment works? This is the puzzle our project addresses.
The classificatory question: What is this procedure called?
Our question: What role is it taken to play within the trial?
04
Our Proposal: Epistemic Perspectives
One way of clarifying this disagreement is to ask what epistemic perspective structures the trial. By epistemic perspectives, we do not mean merely different terminological choices or personal views. We mean background assumptions that shape:
-
①
What counts as the intervention
-
②
What is causally primary — i.e., the causal variable that is under intervention
-
③
What the trial is designed to test
05
Two Epistemic Perspectives
For present purposes, we focus on two contrasting perspectives in the interpretation of psychedelic trials.
What is causally primary
The relation between drug-induced experience and therapeutic effect
What the trial tests
Whether the drug-induced experience is associated with therapeutic improvement
Role of SNP
Support, safety procedures, or controlled background conditions
What is causally primary
The relation between drug-induced experience and therapist interaction
What the trial tests
How the drug facilitates a psychotherapeutic process
Role of SNP
Part of the relational context through which the intervention works
More on DAP — the MAPS example
DAP reasoning within an RCT design
The MAPS example shows a methodological tension within DAP.
The trial uses an RCT structure: MDMA plus manualized psychotherapy is compared with placebo plus the same psychotherapy. On the surface, this makes MDMA appear to be the main variable under test.
However, the MAPS model assumes that MDMA works by catalyzing a therapeutic process. The therapeutic effect is understood to arise from the interaction among drug-induced experience, the therapeutic setting, and the participant–therapist relationship.
The tension is that psychotherapy is treated as essential in the therapeutic model, but held constant in the RCT design. The drug–therapy interaction is therefore causally central in the model, but not directly manipulated in the trial.
For a detailed analysis, see: Yan et al. (2025) ↗
What the Perspectives Clarify
The contrast between a drug-centered and a drug-assisted perspective helps explain why Goodwin et al. (2023) and Villiger (2025) assign different roles to similar procedures.
Goodwin et al. (2023)
Can be read as closer to a drug-centered perspective:
the surrounding procedures are treated mainly as support, safety procedures, or controlled background conditions.
Villiger (2025)
Can be read as closer to a drug-assisted perspective:
the surrounding procedures help structure the therapeutic relationship through which the drug-induced experience becomes clinically meaningful.
What this shows
The disagreement is not only about what SNP are called. It is also about how they are situated within the trial: as background conditions, or as part of the causal process under investigation.
References
Citations appear as [n] throughout the text.
[1]
Coverdale & Cook (2023).
Mechanisms of integration in psychedelic-assisted therapy.
Shows that psychedelic-assisted psychotherapy is commonly described through preparation, in-session support, and integration phases.
[2]
Boehlke et al. (2024).
Cochrane review on psychedelic-assisted therapy for anxiety, depression, and existential distress in life-threatening disease.
Defines included interventions as psychedelic experiences preceded by preparatory therapeutic sessions and followed by integrative therapeutic sessions.
[3]
Brennan, Kelman & Belser (2023).
A Systematic Review of Reporting Practices in Psychedelic Clinical Trials.
Documents underreporting of psychosocial interventions, including session number, duration, provider credentials, manuals, and fidelity.
[4]
Swainson et al. (2026).
Ketamine, Psychedelics, and Psychotherapy: Reframing, Redefining, Renaming Treatment Models.
Argues that studies often fail to distinguish manualized psychotherapy, psychological support, psychoeducation, and integration-focused therapy.
[5]
Richard & Levine (2025).
What is Psychological Support in the Context of Psychedelic Clinical Trials?
Describes psychological support as poorly defined and calls for clearer boundaries between psychological support and psychotherapy.
[6]
Pronovost-Morgan et al. (2025).
ReSPCT guidelines.
Recommends reporting extra-pharmacological variables including physical environment, dosing procedure, therapeutic framework, and participant experience.
[7]
Brusky et al. (2026).
Psychological support in psychedelic-assisted therapy clinical trials.
Frames psychological support as ambiguously conceptualized either as a vector for therapeutic change or as a framework for risk minimization.
[8]
Goodwin, Malievskaia, Fonzo & Nemeroff (2024).
Must Psilocybin Always 'Assist Psychotherapy'?
Argues that psychological support in recent psilocybin trials is primarily directed toward safety and should not automatically be treated as psychotherapy.
[9]
Goodwin et al. (2022).
Single-Dose Psilocybin for a Treatment-Resistant Episode of Major Depression.
Provides the COMP360 trial context discussed in later debates about psilocybin treatment, psychological support, and psychotherapy.
[10]
Villiger (2025).
The patient–therapist relationship in psychedelic-assisted treatment.
Argues that PAT combines pharmacological and psychological interventions, and that non-directive support may still have psychotherapeutic significance when it is process-directive.
[11]
Zamaria et al. (2025).
Psychedelics assisting therapy, or therapy assisting psychedelics?
Frames the broader controversy over whether psychotherapy should be included as a component of psychedelic-assisted therapy.