Phenomenological Taxonomies in Psychedelic Research: Insights from Yoga Vāsiṣṭha

New Framework: From Triggers to Phenomenology in Altered States

The 2026 review published via OpenAlex (W7222864490) presents a significant shift in how psychedelic and hypnosis research conceptualizes altered states of consciousness. Instead of labeling states by their triggers—such as 'psychedelic', 'hypnotic', or 'meditative'—the review argues for a taxonomy based on the phenomenological qualities of the experience itself. This proposal draws from recent consensus taxonomies in the field, as well as ancient frameworks like the Yoga Vāsiṣṭha, and synthesizes evidence presented at the 2026 Society for Clinical and Experimental Hypnosis (SCEH) conference.

Key findings from the review include the observation that different induction methods—psilocybin, hypnosis, or suggestion—can produce similar phenomenological states, such as unity, altered identity, or detachment. The review further notes that the intensity of a mystical-type experience during a first psilocybin session predicts clinical benefit, but repeated mystical experiences do not necessarily yield proportional therapeutic gains. This insight challenges the assumption that more frequent or intense altered states always translate to better outcomes and highlights the need for more precise models.

The Context–State–Stance–Trait Model and Fundamental Peace

The review introduces the Context–State–Stance–Trait (CSST) model as a layered approach to understanding altered states. This model distinguishes between:

• Context: The situational and environmental factors surrounding the experience
• State: The phenomenological qualities of the altered state itself
• Stance: The individual's orientation or attitude toward the state, drawing on the Yoga Vāsiṣṭha's seven stages of knowledge (jñāna-bhūmikā)
• Trait: Enduring characteristics or capacities that persist after the experience

Central to this framework is the construct of 'Fundamental Peace,' operationalized through the FP20 scale, which measures both the immediate stance during an altered state and the lasting capacity for equanimity or emotional regulation. The review links these concepts to brain network dynamics, specifically the default mode, salience, and executive control networks, suggesting a neurobiological substrate for the observed psychological changes.

This approach enables researchers to test whether it is the state itself, the context, or the individual's stance that mediates lasting therapeutic change—a distinction that has been elusive in prior research. Notably, the review proposes using hypnosis as an experimental control for psychedelic research, as hypnosis can occasion similar phenomenological states without the pharmacological confounds of psychedelics.

Implications for Clinical Trials and Mechanistic Research

The adoption of phenomenological taxonomies and the CSST model has direct implications for the design and interpretation of psychedelic clinical trials. By focusing on the qualities of the experience rather than its trigger, researchers can better isolate the mechanisms underlying therapeutic outcomes. For example, the review highlights that mystical experience intensity at a first psilocybin dose predicts response in treatment-resistant depression (see Brudner et al., 2025), but repeated dosing does not linearly increase benefit—suggesting diminishing returns or a ceiling effect.

Furthermore, the proposal to use hypnosis as a control condition addresses a longstanding challenge in psychedelic science: the difficulty of blinding and controlling for expectancy effects. Hypnosis-induced mystical experiences, while phenomenologically similar to those induced by psychedelics, have not yet demonstrated comparable clinical efficacy. This discrepancy offers a unique opportunity to disentangle the contributions of state, context, and stance in future studies.

One non-obvious implication surfaced in the review is that current regulatory and trial frameworks may be inadvertently privileging pharmacological triggers over potentially safer, non-drug interventions that can occasion similar states. This could have downstream effects on access, safety, and the ethical landscape of psychedelic-assisted therapies.

Risks, Unknowns, and Research Gaps

While the phenomenological approach offers greater mechanistic clarity, it also introduces new complexities and risks. The operationalization of constructs like 'Fundamental Peace' and the FP20 scale remains in early stages, and their predictive validity for clinical outcomes is not yet established. Additionally, the use of hypnosis as a control, while promising, may not fully account for the unique pharmacodynamic and subjective effects of psychedelics.

There is also a risk that shifting focus from triggers to phenomenology could obscure important safety considerations tied to specific substances or methods. For example, while hypnosis may be safer physiologically, it may not be appropriate for all populations or indications. The review notes that more research is needed to determine whether stance or trait-level changes mediate long-term benefit, and whether these can be reliably measured across diverse settings and populations.

Looking Forward: Toward a Unified Science of Altered States

The field of psychedelic research stands at a methodological crossroads, with the proposed phenomenological taxonomy and CSST model offering a roadmap for more rigorous, mechanism-driven science. By integrating ancient frameworks like the Yoga Vāsiṣṭha with contemporary neuroscience and clinical trial design, researchers may be able to clarify the pathways from extraordinary experience to lasting change.

Future research will need to validate the Fundamental Peace construct, refine measurement tools like the FP20 scale, and test the CSST model across different interventions and populations. Regulatory agencies and trial sponsors should consider these frameworks when designing protocols, as they may improve both experimental control and the generalizability of findings. Ultimately, this approach could help the field move beyond debates over triggers and toward a deeper understanding of what truly mediates therapeutic benefit in altered states of consciousness.

How we research: This article was written by Dr. Alex Brudner, PhD (Neuroscience, Yale), and reviewed by Dr. Priya Majeti, MD (Psychiatry, Stanford) on 2026-10-20. Primary sources include the cited OpenAlex review, SCEH 2026 conference proceedings, and referenced peer-reviewed studies.