¿Cómo es la terapia con ketamina? Repasando 5 años de viajes

Michael DeMarco, PhD

Psychedelic Mental HealthMichael DeMarco, PhD

Psychedelic is the word given to describe any medicine or practice that can lead to an inner experience described in English as altered states of consciousness. Ketamine is a generic medication used in humans and animals since 1962, and is often described as involving this psychedelic experience. In very high doses, it has been safely used as surgical anesthesia within an anesthetic class described as "dissociative anesthesia" since it was approved by the FDA in 1970. It has a long history of being prescribed off-label for a range of pain and mental health indications.

I began specializing in ketamine therapy and facilitation as a psychedelic therapist in 2021. I developed a program to train others in cognitive-behavioral mental health, both in-person and virtually, to support the therapeutic use of ketamine for physical and mental pain, as well as addictions.

This is what journey reports have revealed after 5 years of practice. Edits are ongoing as additional analysis is available.

Pahnke and Richards defined the psychedelic/mystical experience using core categories derived from Walter Stace's phenomenology of mysticism. In this dataset from 5 years of private practice, several of these core dimensions rank exceptionally high:

• Transcendence of time and space: 91 mentions (8.28% of total tags)
• Internal unity: 90 mentions (8.19% of total tags)
• Objectivity and reality (noetic quality): 75 mentions (6.82% of total tags)
• Ineffability: 72 mentions (6.55% of total tags)

Pahnke originally used these same subscales to measure whether participants undergoing high-dose LSD sessions achieved a "complete mystical experience." The ketamine dataset from 5 years of private practice in ketamine therapy shows a strong concentration in these specific categories, indicating that ketamine is capable of producing the profound ego dissolution, boundary loss, and noetic perceptions traditionally associated with classic serotonergic psychedelics like LSD or psilocybin.

Pahnke and Richards emphasized that experimental mysticism produces positive and significant after-effects rather than mere transient confusion. This ketamine data shows:

• Positive changes in attitude and behavior: 100 mentions
• Deeply felt positive mood state: 94 mentions

This reflects the therapeutic and transformative outcomes that Pahnke and Richards documented in their research on experimental mysticism.

Although ketamine is technically classified pharmacologically as a dissociative anesthetic (acting primarily as an NMDA receptor antagonist rather than a 5-HT2A receptor agonist like LSD), Pahnke and Richards' theoretical framework is phenomenological. That means it evaluates the subjective state of consciousness achieved rather than the specific neurochemical pathway. What is the EXPERIENCE you have when you work with a psychedelic medicine or practice?

This data demonstrates that, on a functional level, ketamine journeys traverse the same psychological territory (unity, transcendence, the sacred, and ineffability) that Pahnke and Richards charted for classic psychedelics, like LSD.

Ketamine Psychedelic Psychotherapy: Focus on its Pharmacology, Phenomenology, and Clinical Applications

Meant to be an authoritative guide for psychiatrists and others interested in understanding and applying ketamine psychedelic psychotherapy (KPP), this paper focuses on its pharmacology, phenomenology, and clinical applications. Ketamine is a dissociative anesthetic widely used by physicians and veterinarians in the United States. In addition to its anesthetic and dissociative properties, ketamine also has a multitude of other psychological and pharmacological properties, which include analgesic, sedative, neuroprotective, anxiolytic, antidepressant, stimulant, euphoriant, and hallucinogenic effects. The literature on the clinical application of KPP is comprehensively reviewed, practical advice for using KPP is given, and the pharmacology and phenomenology of ketamine-induced psychedelic experiences are explored, including in relationship to transpersonal healing and possible iatrogenic consequences of misuse of KPP.

Digital Commons @ CIISEli Kolp

In 2014, Kolp and fellow researchers write:

"In addition to its anesthetic and dissociative properties, ketamine also boasts a multitude of other psychological and pharmacological properties, including analgesic, sedative, neuroprotective, anxiolytic, antidepressant, stimulant, euphorigenic, and hallucinogenic effects. The literature on the clinical application of ketamine psychedelic psychotherapy (KPP) is thoroughly reviewed, practical advice for its use is provided, and the pharmacology and phenomenology of ketamine-induced psychedelic experiences are explored, including in relation to transpersonal healing and possible iatrogenic consequences of the misuse of KPP"

They go on to describe four types of ketamine psychedelic experiences as Empathogenic, Out of Body (OBE), Near Death Experiences (NDE), and Ego-Dissolving Transcendent experiences. In 5 years of practice, only 7 people had an experience that was different than the four experiences described in research. (Kolp et al., 2014). Definitions for each are included.

Most journeys, across a range of doses, routes of administration and clinical settings including at home, only 7 journeys were marked as being something different than Kolp's four experience categories. Most people fell in the Empathogenic range. 76 people described their journey as a Near Death Experience and/or Ego-Dissolving Transcendental Experience, and 68 as an Out of Body Experience.

Compare this again to Pahnke & Richards (1966)

• Transcendence of time and space: 91 mentions (Ego-Dissolving Transcendental State)
• Internal unity: 90 mentions (Empathogenic)
• Objectivity and reality (noetic quality): 75 mentions (Near Death Experience)
• Ineffability: 72 mentions (Out of Body Experience)

After ketamine therapy, people marked whether they thought ketamine was right for them. This was collected from 2 sets of client and trainee cohorts with one practitioner, and a smaller set, third cohort with a practitioner apprentice and clinical fellow, Dominique Condeveau.

Total Combined Results (All 3 Groups)

The ketamine medicine session was helpful for me: in 162 journeys, people marked Yes, in 7, journeys, people marked that they did Not think that medicine session was helpful. Sometimes this field wasn't completed.

These scores reflect the journeyor's reflection of a particular medicine session, and not ketamine therapy overall. Journey satisfaction is sometimes affected by technical difficulties, or journey expectations, as well as how the individual is feeling in the days following the journey at the time of completing their integration questionnaire. Psychedelic integration questionnaires include a qualitative section asking about the most positive aspects and negative aspects of their medicine session, still to be analyzed.

Samples: What was the most negative or difficult part of your experience? Stuffy nose afterward.

What was your intention before taking the medicine? How did your experience reflect your intention? How have you been incorporating this into your daily life?Wanting to see if a low dose would bring back or repeat past journeys. I am reminded by the experiences after the journey by the music I listen to again, after the journey.

What were you able to remember, carry forward, and/or complete that you had intended in your treatment? Yes, I am reminded and aware of being all - all the time. Tremendous responsibility and blessing at the same time.

What visions or information were you able to bring home to your community about your medicine work? Try being God for a day - just for a day!

Ketamine clients and trainee questionnaires reported 197 No thoughts of self harm currently or within the last 6 months, and over the 5 year period, 7 instances of thoughts of self harm within the last 6 months, although noted that this was pre-treatment with ketamine.

14 experiences over five years were reported with Nausea, Increased Heart rate (Tachycardia) or stomach contractions (amounting to a little over 1 % of the time). Psychotic phenomena / Disorientation was marked 9 times (See fuller definition of these terms in the above, as these are commonly seen effects in other psychedelic medicines.

Within the context of psychedelic-assisted therapy, these effects were within normal range of effects as represented in decades of studies.

Edits and analysis ongoing.

In 2025, the NDE-C was one of the assessments given after each journey.

Here is an introductory analysis, including the total number and percentage of individual journeys meeting the NDE threshold (scoring 27 or higher):

• Total Entries Evaluated: n=53
• Individual entries scoring 27 or Over (NDE Threshold): 24
• Percentage of Total Individual entries: 45.28%
• 24 out of 53 journeys, or 45% were considered by the NDE-C as Near Death Experiences (NDE).

Detailed Question Breakdown (Ordered from Highest to Least Scored on a Scale from 0-4)

Key Dimensions Driving the Total Score (Correlation)

Analyzing which specific questions have the highest statistical correlation with the highest overall scores:

• Q9 (Awareness beyond ordinary senses): Correlation of 0.78 with the total score.
• Q4 (Sudden understanding of everything about oneself, others, or the universe): Correlation of 0.75.
• Q1 (Altered perception of time): Correlation of 0.71.
• Q6 (Feeling of harmony or unity with a greater whole): Correlation of 0.71.

This indicates that while peace and well-being (Q5) accumulate the highest absolute scores- people rate this the most often, the experiences statistically defining the highest overall total scores are strongly driven by awareness beyond ordinary senses (Q9) and sudden understanding of everything about oneself, others, or the universe (Q4).

Factor Analysis: Near-Death Experience Content (NDE-C) Scale — Uruguay Sample ($N = 53$)

An Exploratory and Confirmatory Factor Analysis (EFA/CFA) mapping against the validated 5-factor structural model established by Martial et al. (2020) was conducted on the dataset ($N = 53$) of ketamine journeys by mouth at home during a period of 2025-2026.

The NDE-C scale's 20 items cluster into five distinct phenomenological dimensions underlying non-ordinary states of consciousness.

Summary of the Five Latent Factors

Detailed Dimension Breakdown

1. Factor I: Harmony & Affective State

• Items Included: Q5, Q6.
  
• Interpretation: Captures the profound emotional stabilization, feelings of interconnectedness, and intrinsic peace reported by experiencers (Greyson, 1983). In 53 ketamine medicine sessions over 2025-2025, people chose, Q5 (Peace and well-being) the most, yielding the highest single-item aggregate score ($122$), demonstrating that affective (emotional) integration serves as a foundational core element across the cohort.

Compare this to Kolp's Empathogenic type journey described above.

2. Factor II: Beyond the Usual (Perceptual Alterations )

• Items Included: Q1, Q8, Q9, Q11.
  
• Interpretation: Represents spatial-temporal distortions and hyper-vivid sensory processing. Items such as altered time perception (Q1) and out-of-body sensations (Q11) heavily load onto this factor, showing robust internal consistency within non-ordinary experiential frameworks (Timmermann et al., 2018).

Compare this to Kolp's Ego-Dissolving Transcendental Experience described above.

3. Factor III: Insight & Cognitive Processing

• Items Included: Q2, Q4, Q10, Q13, Q20.
  
• Interpretation: Measures cognitive acceleration, sudden unshakeable comprehension, and the persistent challenge of expressing the experience verbally (ineffability, Q20). This domain bridges analytical restructuring with post-conscious integration.
  

This also overlaps with Kolp's Ego-Dissolving Transcendental type experience described above.

4. Factor IV: Border & Transition

• Items Included: Q15, Q16, Q17, Q18.
  
• Interpretation: Encompasses existential thresholds, encounters with the void, and decisions regarding return.

Compare this to Kolp's OBE, NDE or EDT experience descriptions discussed above.

5. Factor V: Gateway & Spatial Departure

• Items Included: Q3, Q7, Q12, Q14, Q19.
  
• Interpretation: Characterized by classical transcendent topographies, including light phenomena (Q7), tunnel/portal entry (Q19), and entity encounters (Q14). Entity encounters were reported in 21 out of 53 ketamine journeys in this period, at least once.

This too is mirrored in Kolp's 4 ketamine experience types discussed above.

References

• Greyson, B. (1983). The Near-Death Experience Scale: Construction, reliability, and validity. Journal of Nervous and Mental Disease, 171(6), 369–375. https://med.virginia.edu/perceptual-studies/wp-content/uploads/sites/360/2017/01/NDE17.pdf
  
• Martial, C., Cassol, H., Charland-Verville, V., Pallavicini, C., Gosseries, O., Laureys, S., & Greyson, B. (2020). Near-death experience content (NDE-C) scale: Development and psychometric validation. Consciousness and Cognition, 86, 103049. https://doi.org/10.1016/j.concog.2020.103049

These forms were completed within 1-4 days of ketamine, usually by mouth, and usually taken at home with an emergency contact checking in every 20 minutes. The initial 4-6 medicine journeys included practitioner support. Subsequent doses were self-administered as directed by their individually licensed medical provider in doses common for mental health and pain indications for use outside of clinical settings as supported in ongoing review of the literature.

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