ArticlePDF Available

Patient Experiences of Psilocybin-Assisted Psychotherapy: An Interpretative Phenomenological Analysis



The psychological mechanisms of action involved in psilocybin-assisted psychotherapy are not yet well understood. Despite a resurgence of quantitative research regarding psilocybin, the current study is the first qualitative study of participant experiences in psilocybin-assisted psychotherapy. Semistructured interviews were carried out with 13 adult participants aged 22 to 69 years (M = 50 years) with clinically elevated anxiety associated with a cancer diagnosis. Participants received a moderate dose of psilocybin and adjunctive psychotherapy with an emphasis on the process of meaning-making. Verbatim transcribed interviews were analyzed by a five-member research team using interpretative phenomenological analysis. General themes found in all or nearly all transcripts included relational embeddedness, emotional range, the role of music as conveyor of experience, meaningful visual phenomena, wisdom lessons, revised life priorities, and a desire to repeat the psilocybin experience. Typical themes found in the majority of transcripts included the following: exalted feelings of joy, bliss, and love; embodiment; ineffability; alterations to identity; a movement from feelings of separateness to interconnectedness; experiences of transient psychological distress; the appearance of loved ones as guiding spirits; and sharing the experience with loved ones posttreatment. Variant themes found in a minority of participant transcripts include lasting changes to sense of identity, synesthesia experiences, catharsis of powerful emotion, improved relationships after treatment, surrender or “letting go,” forgiveness, and a continued struggle to integrate experience. The findings support the conclusion that psilocybin-assisted psychotherapy may provide an effective treatment for psychological distress in cancer patients. Implications for theory and treatment are discussed.
Journal of Humanistic Psychology
1 –35
© The Author(s) 2017
Reprints and permissions:
DOI: 10.1177/0022167817706884
Patient Experiences
of Psilocybin-Assisted
An Interpretative
Alexander B. Belser1, Gabrielle Agin-Liebes2,
T. Cody Swift3, Sara Terrana4, Neşe Devenot5,
Harris L. Friedman6,7, Jeffrey Guss8,
Anthony Bossis8, and Stephen Ross8
The psychological mechanisms of action involved in psilocybin-assisted
psychotherapy are not yet well understood. Despite a resurgence of
quantitative research regarding psilocybin, the current study is the
first qualitative study of participant experiences in psilocybin-assisted
psychotherapy. Semistructured interviews were carried out with 13 adult
participants aged 22 to 69 years (M = 50 years) with clinically elevated
anxiety associated with a cancer diagnosis. Participants received a moderate
1New York University, New York, NY, USA
2Palo Alto University, Palo Alto, CA, USA
3Johns Hopkins School of Medicine, Baltimore, MD, USA
4University of California, Los Angeles, CA, USA
5University of Pennsylvania, Philadelphia, PA, USA
6Goddard College, Plainfield, VT, USA
7University of Florida, Gainesville, FL, USA
8New York University School of Medicine, New York, NY, USA
Corresponding Author:
Alexander B. Belser, New York University, 240 Greene ST 8th FL, New York, NY 10003,
706884JHPXXX10.1177/0022167817706884Journal of Humanistic PsychologyBelser et al.
2 Journal of Humanistic Psychology 0(0)
dose of psilocybin and adjunctive psychotherapy with an emphasis on the
process of meaning-making. Verbatim transcribed interviews were analyzed
by a five-member research team using interpretative phenomenological
analysis. General themes found in all or nearly all transcripts included
relational embeddedness, emotional range, the role of music as conveyor
of experience, meaningful visual phenomena, wisdom lessons, revised life
priorities, and a desire to repeat the psilocybin experience. Typical themes
found in the majority of transcripts included the following: exalted feelings
of joy, bliss, and love; embodiment; ineffability; alterations to identity; a
movement from feelings of separateness to interconnectedness; experiences
of transient psychological distress; the appearance of loved ones as guiding
spirits; and sharing the experience with loved ones posttreatment. Variant
themes found in a minority of participant transcripts include lasting
changes to sense of identity, synesthesia experiences, catharsis of powerful
emotion, improved relationships after treatment, surrender or “letting
go,” forgiveness, and a continued struggle to integrate experience. The
findings support the conclusion that psilocybin-assisted psychotherapy may
provide an effective treatment for psychological distress in cancer patients.
Implications for theory and treatment are discussed.
anxiety, psychosocial distress, cancer, psilocybin, psychedelic, hallucinogens,
qualitative, spirituality, interpretative phenomenological analysis
In the past 15 years, there has been a renaissance of quantitative research
evaluating the safety and efficacy of substances used to alter consciousness,
namely those called hallucinogens and psychedelics (Friedman, 2006;
Studerus, Kometer, Hasler, & Vollenweider, 2011). One of these studied, psi-
locybin, is a naturally occurring serotonergic (4-phosphoryloxy-N,N-dimeth-
yltryptamine) compound found in over 180 species of mushrooms that has
been used in religious and healing practices in various cultures for centuries
(Allen & Arthur, 2005; Stamets, 1996; Wasson, 1980). In a series of double-
blind placebo-controlled trials using quantitative research methods, the pro-
vision of psilocybin-assisted psychotherapy was associated with decreased
levels of anxiety among cancer patients (Grob et al., 2011), reductions in
depressive symptoms among patients with treatment-resistant depression
(Carhart-Harris et al., 2016), positive changes in personality, such as increases
in openness to new experience (MacLean, Johnson, & Griffiths, 2011), and
profound spiritual and mystical experiences (Griffiths, Richards, Johnson,
McCann, & Jesse, 2008).
Belser et al. 3
The current study draws from a subsample of participants from a recently
completed trial conducted by Ross et al. (2016) at New York University
(NYU). In this double-blind placebo-controlled randomized trial, psilocybin-
assisted psychotherapy was investigated as a treatment for patients with can-
cer and concomitant anxiety and depression. The NYU study and a similar
trial completed by Griffiths and colleagues at Johns Hopkins University sug-
gest that a single administration of moderate to high-dose psilocybin, when
combined with psychotherapy, led to rapid, substantial, and enduring
decreases in depression and anxiety, as well as improvements in cancer-
related demoralization and hopelessness, spiritual well-being, and quality of
life (Griffiths et al., 2016; Ross et al., 2016). In the trial conducted at NYU,
the administration of psilocybin generated very large anxiolytic and antide-
pressant effects, with 83% of participants in the psilocybin-first group, as
compared with 14% in the placebo-first group, demonstrating antidepressant
response after 7 weeks. These large magnitude effects were enduring: At
6½-month follow-up, antidepressant and anxiolytic response rates were 60%
to 80% (Ross et al., 2016). Additionally, more than two thirds (70%) of the
study participants rated their experience of psilocybin to be among the top
five most spiritual experiences of their lives. Despite the profound and singu-
lar experiences reported in these quantitative studies (Griffiths et al., 2008;
Griffiths et al., 2011; Griffiths et al., 2016; Ross et al., 2016), we found no
qualitative studies of patient experiences of psilocybin-assisted psychother-
apy in clinical trials in the published literature.
A review of the qualitative literature regarding subjective psychedelic
experiences reveals a variety of studies, although most involve noncompa-
rable participant populations and contexts. Relevant research includes analy-
ses of interviews with substance users in uncontrolled recreational settings
(Beck & Rosenbaum, 1994; Comis & Noto, 2012; Pennay & Moore, 2010;
Singer & Schensul, 2011), user experience reports found on online message
boards (Bersani et al., 2014; Kjellgren & Soussan, 2011), or interviews of
participants involved in non-Western treatment settings (Loizaga-Velder &
Verres, 2014; Presser-Felder, 2013; Shanon, 2002). Various substances have
been investigated using qualitative methods, including ayahuasca (Loizaga-
Velder & Verres, 2014; Presser-Felder, 2013; Shanon, 2002), salvia divino-
rum (Addy, Garcia-Romeu, Metzger, & Wade, 2015); 25C-NBOMe (Bersani
et al., 2014), 4-HO-MET (Kjellgren & Soussan, 2011), MDMA (Passie,
2012; Comis & Noto, 2012; Singer & Schensul, 2011; Beck & Rosenbaum,
1994), and polysubstance use (Pennay & Moore, 2010). Other qualitative
research with psychedelic substances has focused on religious/spiritual/mys-
tical experiences (Yaden et al., 2016) or self-transcendent experiences occa-
sioned by hallucinogens (Garcia-Romeu, Himelstein, & Kaminker, 2015).
4 Journal of Humanistic Psychology 0(0)
Although there are beginning efforts using qualitative inquiry into the
nature of psychedelic experience, rigorous qualitative investigations of the
subjective effects of serotonergic hallucinogens in clinical treatment settings
are rare. In one trial, Turton, Nutt, and Carhart-Harris (2014) conducted an
interpretative phenomenological analysis (IPA) of the subjective experiences
of psilocybin as administered via intravenous injection to healthy psyche-
delic experienced volunteers within a unique setting, an fMRI scanner. In a
second study, Gasser, Kirchner, and Passie (2014) conducted a qualitative
content analysis of LSD-assisted psychotherapy for anxiety associated with a
life-threatening disease. Finally, in their research regarding the administra-
tion of psilocybin to healthy normal volunteers, Griffiths et al. (2008, 2011)
have provided excerpted verbatim comments from participants, and they are
currently pursuing qualitative research with psilocybin (Noorani, Garcia-
Romeu, Griffiths, & Johnson, 2015).
Current theoretical conceptualizations regarding the psychological mech-
anisms of action involved in psychedelic-assisted psychotherapy remain
underdeveloped. Some have proposed that a psychedelic-occasioned mysti-
cal or peak experience is a mediating factor fostering highly salient spiritual/
mystical states of consciousness associated with enduring positive effects in
cognition, affect, behavior, and spirituality (Gasser, Kirchner, & Passie,
2014; Griffiths et al., 2008; Griffiths et al., 2011; Griffiths, Richards,
McCann, & Jesse, 2006; Pahnke, 1969; Studerus et al., 2011). While there is
empirical support for this conceptualization (Griffiths et al., 2008; Griffiths
et al., 2016; Ross et al., 2016), alternative hypotheses regarding other pos-
sible mediating factors and psychological mechanisms of action have not yet
been evaluated.
Quantitative methods are well suited for hypothesis testing, but such
methods may be limited by preconceptions regarding the phenomena under
study. Alternatively, qualitative methods provide a hypothesis-generating
mode of inquiry that is appropriate to address research questions in a nascent
field such as psychedelic science where theoretical models are not yet well
formed. While both modes of inquiry provide value, qualitative inquiry can
complement existing quantitative research regarding psychedelic-assisted
treatments as it is well suited to address questions of meaning, inner experi-
ence, and behavioral change within complex multidimensional contexts
(McAdams, 1999) and may help elucidate underlying mechanisms of action.
Our study is perhaps the first formal qualitative inquiry regarding partici-
pant experiences in psilocybin-assisted psychotherapy. Per inclusion criteria,
all study participants had elevated clinical anxiety and psychological distress
associated with a diagnosis of cancer. The interviews with participants elic-
ited substantial experiences related to cancer, death, and spirituality that have
Belser et al. 5
been analyzed and submitted for other publication (Swift et al., in press), but
our current research question is not focused on oncological concerns. In the
current analysis, we address research questions regarding the form and con-
tent of participant experiences during the psilocybin dosage sessions, descrip-
tions of their subjective experiences of this psychological intervention in
context, and their understandings of the embedded meanings of their lived
Thirteen participants were recruited who had previously been enrolled in a
Phase II clinical trial approved by the institutional review board of the NYU
School of Medicine. The primary objective of this quantitative double-blind,
crossover, placebo-controlled pilot study was to assess the efficacy and safety
profile of psilocybin in conjunction with psychotherapy on psychosocial distress
associated with cancer. Secondary data were also gathered using measures of
depression, existential/psychospiritual distress, pain, attitudes toward disease
progression, quality of life, and spiritual/mystical states of consciousness.
Participants underwent 3 months of treatment, which included the follow-
ing: two drug administration sessions, separated by 7 weeks, a total of nine
sessions of adjunctive psychotherapy with two licensed psychotherapists
conducted before, between, and after the two 8-hour drug administration ses-
sions, and 6 months of follow-up assessment. Regarding the two drug admin-
istration sessions: Participants were randomly assigned to one of two oral
dosing sequences: first, psilocybin (0.3 mg/kg) and second, niacin (250 mg)
or first, niacin (250 mg) and second, psilocybin (0.3 mg/kg). During the drug
administration sessions, participants were encouraged to lie comfortably on a
couch wearing eyeshades and to listen to preselected music. Two study thera-
pists remained with the participant throughout the entire 8-hour sessions.
Eligible participants were between 18 and 76 years of age (M = 50 years), had
a projected life expectancy of at least 1 year, and a primary diagnosis of acute
stress disorder, generalized anxiety disorder, anxiety disorder due to cancer,
or adjustment disorder with anxiety, as assessed by the Structural Clinical
Interview for DSM-IV-TR Axis I Disorders–Patient Version (First, 2005). We
selected a subsample of 13 participants from this quantitative study for inclu-
sion in the qualitative study based on the date of their final drug administra-
tion session. We approached the 14 participants who had most recently
completed drug administration sessions, of which 13 agreed to participate in
6 Journal of Humanistic Psychology 0(0)
the qualitative study as described in Table 1. Five of these participants were
interviewed within 1 week following their second psilocybin dosage session,
and eight of these participants were interviewed at approximately 1-year fol-
low-up. Participants were informed that agreeing to be interviewed was
entirely optional and would have no effect on their involvement in the quan-
titative study. They were offered no financial compensation, and there were
no penalties for declining to participate. All volunteers gave their informed
consent prior to participation. The study was approved by the institutional
review board of the NYU School of Medicine.
One member of the research team (ABB) conducted all 13 semistructured
interviews, which lasted approximately 1½ to 2 hours, using the interview
protocol in the appendix. The interview consisted of questions regarding the
participant’s experiences before, during, and after their involvement in psilo-
cybin-assisted psychotherapy. As the drug administration sessions were
blinded, participants were first asked to identify which session they believed
to be the psilocybin dosage session, then asked a series of questions related to
that psilocybin session. Specific questions addressed perceptual, emotional,
and memory experiences as well as expectations before the treatment and
effects posttreatment. Questions included in the semistructured interview
guide are provided in the appendix. All interview sessions occurred in person,
except for one that occurred via video linkup. Each interview was audio
recorded in its entirety and then transcribed verbatim. All participant data
were subsequently deidentified to maintain anonymity.
Data Analysis
We explored participants’ experiences using a qualitative method, namely
in-depth interviews employing IPA, “a qualitative research approach com-
mitted to the examination of how people make sense of their major life expe-
riences” (Smith, Flowers, & Larkin, 2009, p. 1). In IPA, semistructured
interviews are analyzed through a systematic, qualitative analysis that draws
from phenomenological, heuristic, and narrative theoretical foundations.
Unlike other phenomenological methods, IPA concerns both the description
of experience and understanding of that experience.
Our interpretative team consisted of four doctoral students and an indi-
vidual with a master’s degree. Our group was guided by a consensus deci-
sion-making process (Schweiger, Sandberg, & Ragan, 1986) with members
rotating in the role of the facilitator. We used a computer-assisted qualitative
Belser et al. 7
Table 1. Participant Demographic Information.
Age, years, M ± SD 50 ± 15.77
Male 54
Female 46
White 92
Multiracial 8
Adjustment disorder with anxiety, chronic 77
Adjustment disorder with anxiety and depressed mood, chronic 15
Generalized anxiety disorder 8
Cancer stage
Stage I 31
Stage II 15
Stage III 31
Stage IV 15
Other 8
Site of cancer
Breast 23
Lymphoma 15
Other 31
Ovarian 31
Marital status
Cohabitation 8
Divorced 8
Married 46
Never married 38
Completed graduation/professional school 54
Graduated 4-year college 31
Part college 15
Religious affiliation
Atheist/agnostic 38
Other Christian 15
Jewish 15
Catholic 8
Other faith/tradition 8
Unitarian 8
Methodist 8
Previous hallucinogen use
Yes 46
No 54
8 Journal of Humanistic Psychology 0(0)
data analysis software (CAQDAS) package with collaborative capabilities,
ATLAS.ti 7.5.4, to analyze the interview transcripts (Muhr, 2014). The ana-
lytic process proceeded as follows. (1) Each interview transcript was read
and reread by two independent reviewers, who made notes that included
descriptive comments, linguistic comments, and conceptual comments. The
reviewers also independently coded the transcript, leading to the develop-
ment of a study codebook using “tags or labels for assigning units of meaning
to the descriptive or inferential information compiled during a study” (Miles
& Huberman, 1994, p. 56). (2) Each transcript was subsequently reviewed by
two independent auditors. The role of the auditors was to review the tran-
script, check the coding and commenting of the two reviewers, and respond
to the coders with feedback about any deviations in terms of coded themes
based on their review. The auditors suggested additional codes or comments
as appropriate and provided feedback to the interpretive team, resulting in the
refinement of the study codebook to accommodate the emerging interpreta-
tive framework. (3) Each transcript was subsequently read by an additional
reader, such that all five members of the interpretative team became familiar
with each of the 13 participant transcripts. The roles of (a) reviewers, (b)
auditors, and (c) reader were rotated for the 13 transcripts. (4) Emergent
themes were identified and tentatively organized. (5) Themes were then
defined in greater detail, subthemes were articulated, and interrelationships
among themes were established. In this way, each transcript was indepen-
dently noted by two independent reviewers and audited by two independent
auditors. These cross-check and independent auditing procedures were
designed to maximize analytic rigor and validity.
Themes were assigned frequency labels of “general,” “typical,” or “variant”
depending on the frequency of occurrence. Themes labeled general occurred
in 12 or 13 of the 13 cases, typical themes occurred in 7 to 11, and variant
themes occurred in a minority (2-6 cases; Hill et al., 2005). A number of
themes were discovered through our analysis, as described in Table 2. The
results described in this publication do not include substantial cancer-related
experiences that are currently being analyzed for other publication.
Relational Embeddedness
All 13 participants described remarkable insights or transformations involving
a significant personal relationship. Once under the influence of psilocybin, par-
ticipants described seeing their loved ones in a new way, often an emotional
Belser et al. 9
process laden with both grief and hope. There were no questions in the inter-
views regarding relationships, but, without prompting, all the interviewees
addressed crucial relational aspects of their experiences. These relationships
were most likely to concern the participant’s father or mother (seven partici-
pants), or romantic partner (five participants). Children also figured promi-
nently: four participants spoke of their relationship with their daughter or son.
Other significant relationships with grandparents, siblings, and previous
romantic partners were also described. Relationships were woven throughout
participant narratives—throughout the histories, memories, hopes, feelings,
Table 2. Theme Frequencies.
Case occurrence
General themes
Relational Embeddedness 13
Emotional Range 13
Role of Music as Conveyor of Experience 13
Meaningful Visual Phenomena 13
Wisdom Lessons 13
Revised Life Priorities 13
Desire to Repeat the Psilocybin Experience 12
Typical themes
Exalted Feeling of Joy or Bliss 11
Feeling Love 11
Ineffability 10
Alterations to Identity During Psilocybin Experience 9
Embodiment 7
From Separateness to Interconnectedness 7
Difficult Struggle: Experiences of Transient
Psychological Distress
Loved Ones as Guiding Spirits 7
Sharing the Experience With Loved Ones 7
Variant themes
Lasting Changes to Sense of Identity 6
Synesthesia Experiences 6
Catharsis of Powerful Emotion 5
Improved Relationships After Treatment 5
Surrender or “Letting Go” Following Transient
Psychological Distress
Forgiveness 4
Integration: Continued Struggle 3
10 Journal of Humanistic Psychology 0(0)
visions, and realizations as reported by the participants. In this way, the psilo-
cybin experience may be conceived as relationally embedded. Mike, a father of
three daughters, described how he was able to more deeply empathize with and
understand the anxieties and fears with which they struggled. He relates the
following transformative vision of his daughters:
Bit by bit, my daughters were turning into these radiant beings, cleansed of all
these fears. It was incredibly emotional, because it was something I have, as
their father, long known, but it’s a very great pain when you see your children
being victimized by fears . . . to see these beautiful beings not realizing their
Later that night, after the psilocybin session, Mike had a powerful moment of
connection with his daughter. He explained the vision he had to one of daugh-
ters, “And she started crying. She came over, and she hugged me and was just
holding onto me, and I knew that I had reached the place that I knew I could
reach in her.” These relational visions brought about catharses, feelings of
forgiveness, and were often emotional catalysts, allowing participants to
move into more expansive feelings of love and peace for themselves and for
the people in their lives.
Sharing Experiences With Loved Ones. Occasionally, participants described
how, in sharing aspects of their experience with loved ones, they drew closer
in their relationships with their daughters, mothers, husbands, or wives. For
example, one participant’s daughter cried when he told her how he had seen
her during the session. When another participant described to his parents his
psilocybin experience, his mother, who had cared for him during his years of
sickness with cancer, began to cry: “It was amazing. It was cathartic. She was
so moved by how moved I was. I think she could tell that it had changed
something profoundly in me.”
Forgiveness. Through the process of coming to see their loved ones in a new way
and with deeper clarity, four participants were able to transform feelings of frus-
tration, anger, and disappointment toward important people in their lives into
acceptance and forgiveness. One participant described coming to “an acceptance
of the human experience.” This acceptance allowed her to release long-held
resentments about past actions committed by her family and others. She said,
I felt like my family was doing their best and that people tried as hard as they
could. And that even people that weren’t there for me did their best, and certain
things from the past were in the past. [pause] And that was okay.
Belser et al. 11
Another participant talked about the shortcomings of her parents. She
described reaching a place of acceptance of and forgiveness for her parents’
mistakes, to which she had felt “like a total stranger.” After her psilocybin
session, she said,
I felt like I let go of a lot of anger and resentment towards my parents. I mean,
I thought I had already done that, but I really hadn’t, and I kind of saw them
more as, like, these flawed human beings who did the best they could.
A third participant described how during the psilocybin session, she was able
to forgive her husband who, while she was sick with cancer, had pursued a
secret affair with another woman. This participant suggested that by coming
to a deeper understanding, she was able to stop “carrying this anger” and
“open up more” to “feeling closeness and love” not only toward him but also
herself. “I allowed myself to just not carry that weight of everything, and to
forgive. . . . And to forgive myself,” she said.
Improved Relationships After Treatment. Five participants described how
their ways of relating to other people changed as a result of their involve-
ment in the study. One participant said that he “stayed in touch with more
people as a result of the study” and strove to “show people that you care
about them, be kind to other people, take care of the people in your life.”
Another described how she now spends more time being with her daugh-
ter, talking to her: “I changed. I just was different. I just felt happier.”
Edna described “a greater understanding of the people around me”; she
speaks of a lasting shift in how she relates to people she encounters in the
People can genuinely care about you even though they really aren’t your loved
ones, and they are not your good friends. Still, they really, you know, they
would miss you if something bad happened to you. And they really, when they
say, “how are you doing?” they really mean that and, and when they say, “Oh
you look great, and I’m so glad you are doing well,” they mean that. Umm, to
be able to accept that—I think to accept that people love me—that, yeah, that
I’m worthy of being loved.
Here, Edna’s ability to love and be loved has changed the deeper meaning of
the everyday pleasantries she exchanges with other people.
Dan, a former bank employee and real-estate investor, described how he
felt a “very blissful connection” to his brother, with whom he was close dur-
ing childhood. He said,
12 Journal of Humanistic Psychology 0(0)
just the way that I was connected to my brother felt very intense in a way that
I don’t feel now, day to day, but—and I remember feeling that way. It was very
strong, and it was very loving, and very like “everything is okay.” It was almost
exciting, this very blissful connection.
Dan also described feeling “a deeper connection with my girlfriend,” who
had, in fact, moved into his apartment the day before his psilocybin session.
He described coming home directly from the session and sitting on his couch
with her. He said:
I was appreciating the pureness of her, if you will, her being, in a way. In a way,
I had not allowed myself, or not realized, or whatever the case was. And so that
was pretty much immediate, but I felt like that had a lasting effect. I feel that
kind of changed my perception of our relationship over the ensuing weeks in a
way. It allowed me to be more open with her, express my appreciation a lot for
her in way that I had not. I think it had a positive effect—kind of a bit of a
snowball effect.
Dan reflected that the state of mind into which he entered helped him become
“more emotionally open” to his girlfriend. Within 3 months, Dan bought an
engagement ring and proposed marriage to her.
Loved Ones as Guiding Spirits
Seven participants described being visited by guiding spirits who helped
them move through their psilocybin experiences; they typically manifested in
the form of visions of loved ones providing guidance or reassurance.
Participants described hearing a guiding voice or seeing a spirit that was a
“being” who aided them along their inner journeys. These guides were
described as recognizable familial figures: In one case, daughters were
described as guiding angels, and in another, a father appeared in visions as a
psychopomp, a guide on the journey. Male participants were more likely to
encounter the presence of such a guide.
One participant, Victor, a young man in his 20s who was diagnosed with
leukemia in high school, described being guided by a spirit that “took the
form of my dad.” This guide propelled Victor through a variety of visionary
landscapes, from “eroded burnt deserts” to sewers and caves. When Victor
became scared, his father reassured him that “everything was going to be
okay” and brought him to a beautiful garden. With the help of his “spirit
guide,” Victor had another powerful vision of affirmation from loved ones
who had passed:
Belser et al. 13
I was flying through space with the spirit guide, and I encountered three people
who are dead who were very close to me. My dad’s dad, my mom’s mom, and
my best friend in college who died. And they all gave me reassuring messages
in space. From my friend Tim, “I’m sorry for everything that has happened. I
just wanted you to know I love you, man.” My grandfather gave me a hug, and
my grandmother kissed me on the cheek. That was powerful.
In Victor’s narrative and in other participant encounters with spirit guides,
what is remarkable is the interpersonal nature of these encounters; just as
Virgil guided Dante through the realms of The Divine Comedy, the partici-
pants in this study were not always solo travelers in their journeys. Rather,
their experiences were often mediated by the presence of a guiding spirit who
helped them navigate novel landscapes and inner realms.
Emotional Range and Catharsis
The emotional experiences reported by participants were notable for their
depth, breadth, number, and cathartic release. All 13 participants reported
having significant emotional experiences during the psilocybin session that
were singular or beyond what they were able to access in their daily lives.
Most described experiencing paramount emotional experiences: 11 partici-
pants reported exalted moments of joy and bliss, and an equal number
reported a deep feeling of love. Concomitantly, participants also described
moments of emotional difficulty like despair, fear, sadness, and grief (see The
Difficult Struggle: Experiences of Transient Psychological Distress section).
Many of the participants commented not only on the wide range of emotions
they accessed but also the sheer multitude of feelings. One participant said he
“experienced all the emotions I know how to experience,” and another said
she felt, “all of them, all of them. Every possible emotion.” Six participants
shed tears during the interview itself when revisiting their experiences.
Participants often experienced widely disparate emotions quickly evolv-
ing from one into another. One participant, for example, traveled in rapid
succession to many different visual scenes and places, from witnessing his
own funeral to climbing a sacred mountain, with a wide range of associated
emotional experiences:
When I was at my funeral there was this tremendous sadness, just like
mourning, collective mourning. When I went through this hellish place,
emotion of despair. When I landed in the garden, I felt relief. At this ball, this
profound joy. When I was shot down to the sewer, I was confused. When I got
shot up to the empire state building, I felt empowered. And then—I don’t know
14 Journal of Humanistic Psychology 0(0)
if it’s an emotion—but once I accepted my body and started climbing this
mountain to try to find this entity, I would say I experienced yearning, yearning
for something higher, something greater, something beyond me. And then at
the very end . . . there was a lot of comfort and relief and reassurance.
This participant came to understand this emotional lability as a meaningful
experience—the feelings that arose were not random but rather situated
within his personal narrative and the arc of his psilocybin experience.
Five participants reported having access to long-held strong or repressed
emotions such as grief, sadness, and traumatic pain. Adam, a young medical
student, had previously dismissed the feeling emotions altogether because “it
doesn’t solve anything, and you have to be strong, or that is what I used to
think.” During his psilocybin session, Adam grieved a broken relationship
with his father. For the first time since he was 6 years old, Adam cried, weep-
ing tears of grief and sadness, which he had held in abeyance for nearly two
decades. This catharsis provided him with a profound sense of relief. Another
participant reported having had, unexpectedly and for the first time in her
life, access to emotions related to childhood sexual trauma. She came to real-
ize the emotional “weight” and “baggage” she was carrying and “had not
dealt with” because “it was too painful, and it was too awful.” In the psilocy-
bin session, with the support of her therapists, she was able to feel and then
release these painful affects. She said, “I feel like what happened was that in
a very short period of intense time I dealt with some really powerful things
and put it behind me.”
The Difficult Struggle: Experiences of Transient Psychological
Seven participants reported experiences of transient psychological or emo-
tional struggle often characterized by acute reactions of fear, confusion, panic,
or paranoia. There were no serious adverse events, either medical or psychiat-
ric, in the trial that were attributed to psilocybin. There was no need for the
administration of pharmacologic interventions (such as benzodiazepines or
antipsychotic medications) and no psychiatric hospitalizations. These reactions
were transient and dissipated or resolved within the supportive treatment con-
text. For example, Edna experienced a “very sudden onset” of the effects of the
psilocybin medication. She emphasized the importance of her therapists’ pres-
ences and the rapport they had developed prior to the session.
It really hit me very strong. And um, it was terrifying. It was just terrifying. It
was, um, I was completely disoriented . . . I was really, maybe, in the hold of a
Belser et al. 15
ship at sea. Rocking. Absolutely nothing, nothing to anchor myself to, nothing,
no point of reference, nothing, just lost in space, just crazy, and I was so scared.
And then I remembered that Tony and Michelle were right there and suddenly
realized why it was so important that I get to know them and they to get to
know me. And reached out my hand and just said “I’m so scared.” And I think
it was Tony who took my hand . . . and said “It’s all right. Just go with it. Go
with it.” And um, and I did.
Here, Edna described feeling unmoored with “no point of reference” and
concomitant feelings of panic and fear. She described how it was important
to have established rapport with her two therapists in the sessions preceding
the psilocybin administration session. The mutual trust they had developed in
the therapeutic relationship helped Edna weather the stormy seas of her
A total of 9 of 13 participants described the experience of losing their
sense of self. One participant felt himself “losing the firm grasp on sort of
‘me-hood,’” including “my past, my relationships, my personality.” Another
described a vision of sets of green eyes seeking him out; he came to the real-
ization that they’re “not going to find me” since “there’s no one to be found.”
The dissolution of normal boundaries of the self sometimes led to a sense of
identity separate from the body: “I didn’t have a body . . . I was just like this
soul, this entity.” One participant described “my consciousness, or my soul,
or whatever, was flying out of my body.”
Only some participants experienced this dissolution of their normal sense
of self as disturbing or arousing of feelings of momentary paranoia that they
would not return. One participant described having the thought that he would
never “get back to normal.” Another participant, Dan, described a disturbing
period of fearfulness and “disintegration” of his identity. For him, this period
of “deadness, of complete disconnectivity” became a “turning point” to
becoming more present in the moment. For Dan, the period of frightening
disintegration was one stage in an unfolding process. Following this turning
point, Dan’s account rings with what he described as “complete clarity,”
I knew exactly who I was, I knew exactly what I was doing here, and beyond
that I was augmented . . . I was just really enthralled . . . everything was delicate
and again, it was not blurry, it was not clouded. Everything was heightened.
Surrender or “Letting Go” Following Transient Psychological Distress. Four partici-
pants recounted that in the midst of intense periods during the psilocybin
experience, their experiences of struggle gave way to an experience variously
16 Journal of Humanistic Psychology 0(0)
described as “surrender” or a “letting go.” They described moving from
defensive resistance into a deeper phase of the experience marked by feelings
of relief, wholeness, freedom, and affirmation. One participant described a
very strong feeling of self-hatred, which resolved by means of a confronta-
tion. She asked herself: “Why would you hate yourself? You’re wonderful, it
makes no sense . . . then there was an immediate relief. It was an awareness.”
Two participants experienced strong feelings of self-doubt that yielded
shortly thereafter to feelings of relief. The sequential progression of these
experiences suggests an arc of experience or a necessary sequence; a partici-
pant’s capacity to surrender in the face of a struggle or frightening encounter
may facilitate an unfolding therapeutic process. In this way, the “incredible
struggle” that is a hallmark of the psilocybin experience may not be an unde-
sirable side effect, but rather a central and necessary feature of participants’
healing narratives.
From Separateness to Interconnectedness
The dissolution of normal identity often led to a feeling of interconnection
with other people, the entire planet, or even the universe at large. Chrissy
came to the realization that life and death are part of one circle, stating “we’re
all kind of a greater whole” and “we’re all going to be connected again in the
universe.” She accessed “a great plane of consciousness” in which “I felt like
I could reach out to anybody and connect with them.” Another participant
described his own feeling of connection to all of humanity: “An overarching
theme of this psychedelic spiritual realm is just like the interconnectedness of
things.” Another participant achieved “a greater understanding of global con-
nectedness . . . It just opens you up and it connects you.” She described the
realization that “everything is connected—you know, it’s not people—it’s
animals, it’s trees—everything is interwoven, and that’s a big relief. It’s a big
comfort.” Others described a feeling of connection to nature and to the greater
Rather than feeling disempowered from being subsumed within a greater
whole, many participants reported new feelings of empowerment and per-
sonal agency to live meaningful lives, and a sense of belonging and accep-
tance within their communities and the larger universe. During his experience,
Mike who experienced a “sense of alienation and separation” in his life prior
to the study described a process of being “welcomed into a group” during his
session and noted, “I was very aware that I belonged there” and “the strength
I derived from that was incredible.” Other participants reported that they had
found their “place in the cosmos” or that they felt “more contented and happy
about my place in the world, in all the things I’m doing.”
Belser et al. 17
One participant received an explicit message of belonging: “I kept hearing
we are here all together, we are here all together,” which brought her “great
comfort.” An “understanding of global connectedness” led Erin to “a feeling
that I wasn’t alone.” This was significant, as Erin had previously felt a great
deal of isolation: “All my life before that, I felt like I was alone.” After the
treatment, this sense of belonging even extended to times when she was phys-
ically alone: “I have kept that feeling ever since.” She added, “It’s the first
time I ever really felt like I was part of the world instead of separate from it.”
The majority of participants described the pernicious effects of cancer and
cancer treatments, such as chemotherapy and surgery, on their bodies. They
describe their difficulty adjusting to physical debilitations and losses, includ-
ing incontinence and premature menopause, as well as the visceral effects of
surgeries and chemotherapy on their bodies. Six participants described com-
plex visions in which their cancer was physically ejected from their bodies or
accepted as part of their physical form. In the former, three participants
described the ejection of cancer, released from their ribcages, abdomen, and
through the tips of their fingers. In the latter, participants described seeing
their physical bodies in a vision, and of choosing to accept their bodies, can-
cer, and all. One participant described a vision in which he saw vestigial
“lumps” of cancerous tumors, now benign, as clear and harmless tissue.
A number of participants described using their hands, breath, voice, or
entire body to physically express or manifest their inner psilocybin experi-
ence. During his experience, one participant moved his hands expressively in
what his therapist described as a “hand ballet.” Another participant described
how his “body was resonating . . . like a string on a violin.” A third participant
described the intentional use of his breath as a “washing element.” Finally,
one participant recounted a moment in her experience when she felt that
“physically . . . most perceptions of my body had just disappeared.”
Wisdom Lessons
Every participant expressed gaining transpersonal insights into the nature of
the universe or existence during the course of their psilocybin session. These
feelings of insight or perceived wisdom lessons were described as extending
beyond participants’ personal histories. The most prominent experiences per-
tained to experiences of direct knowing that were either difficult or impossi-
ble to convey in words. Five participants attested to experiencing revelations
that made metaphysical concepts tangible where they had previously seemed
18 Journal of Humanistic Psychology 0(0)
vague, uncertain, or overly abstract, as one participant stated: “Long have I
known the theory of it, but now I know I feel it.” Among these experiential
understandings were the nature of space-time, the foundational role of love in
the universe, the interconnectedness of all things, and the importance of
experiential understanding. In addition to providing new insights about old
ideas, five participants described arriving at new ideas with a felt sense of
conviction. Among these perceptions were the existence of a parallel level of
reality and the possibility of discarnate perception. These insights were often
described as nonverbal: “You don’t understand it strictly in your head. You
understand it as a being, as a body.”
Ineffability. The nonverbal nature of certain psilocybin-occasioned insights
appeared foundational to many participants, with 10 participants alluding to
ineffability or difficulty characterizing their experiences in words. For exam-
ple, one participant noted: “words fail me,” and another stated, “It’s hard to
describe.” Erin, a woman in her 50s said, “I mean, it’s really hard to describe.
You just know, but you feel it in a very intense way because part of it is in the
process of knowing, you realize that you didn’t know before.” Four partici-
pants described encountering a spiritual reality beyond the capacity of lan-
guage to describe. Meanwhile, seven participants attempted to describe
significant aspects of their experience while simultaneously insisting that
those descriptions did not adequately capture them: “You cannot express
what is happening. You have a complete blockage, because there is no vocab,
there is no word.” Three participants relied on paradoxical juxtapositions of
words to compensate for the limitations of language, using poetic phrases
like “formless mass,” “indescribable confluence of joy and sorrow,” and
“wonderful nothingness.” Augusta vividly embraced simile and metaphor to
communicate her experience:
It was like being inside of nature, and I could’ve just stayed there forever—it
was wonderful. All kinds of other things were coming, too, like feelings of
being connected to everything, I mean, everything in nature. Everything—even
like pebbles, drops of water in the sea . . . it was like magic. It was wonderful,
and it wasn’t like talking about it, which makes it an idea, it was, like,
experiential. It was like being inside a drop of water, being inside of . . . a
butterfly’s wing. And being inside of a cheetah’s eyes.
Despite this difficulty in accurately articulating each experience, eight par-
ticipants felt that their insights arrived from an inner or otherwise enduring
source, to which they could return in ordinary states of consciousness. Three
participants expressed the need to actively integrate their psilocybin insights
into their daily lives in order to continue deriving meaning from them.
Belser et al. 19
Meaningful Visual Phenomena. All 13 participants described perceiving
closed-eye visual phenomena, with varying degrees of complexity. In sim-
pler forms, participants described seeing “patterns on my eyelids,” “the phos-
phorous that you see when you are falling asleep,” and “wonderful computer
graphics.” While aesthetically compelling, these simpler visualizations
remained transient phenomena. Participants also reported seeing more com-
plex visual phenomena described as “visions”—these are contingent, unique,
and subjective phenomena, each of which requires idiographic contextualiza-
tion to understand the vision’s significance.
To illustrate the range of complex visual phenomena, a catalog of experi-
ences is provided. Participants reported seeing various animal figures, includ-
ing “a gorilla face,” “a horse’s eye,” two “serpents,” and “two-colored cow
heads.” The visions often took the form of moving through vast or grand
scenes, such as flying high through the rafters of a Gaudi cathedral; travers-
ing a roller coaster’s hills and valleys in varicolored cars; or gazing on a blue
placid lake with a boatman wearing a white hat on the sandy shore. Some
participants described generating their own worlds through a creative pro-
cess. For example, one participant, while listening to the music soundtrack,
described inventing a massive three-dimensional chessboard world to match
the music—to create a “place where such a song would be played.” Other
participants described reinhabiting vivid scenes from their past, from decades-
old treks through canyons to gazing at a meaningful painting hanging in a
Certainly, this short catalog is neither complete nor does it convey the
richly contextualized meanings (biographical, relational, affective, and psy-
chospiritual) which are associated with these closed-eye visions. These
visions provided multilayered phenomena that became integral to partici-
pants’ meaning-making processes. The visions often became central organiz-
ing motifs through which the participants could draw disparate elements of
their lived experiences into coherent self-narratives.
Synesthesia Experiences. Synesthesia is a perceptual condition in which a
stimulus in one sensory modality, such as hearing, elicits a sensation in
another sensory modality, such as sight. Although we did not ask specifically
about synesthetic experiences, six participants reported having some form of
synesthesia. These include one or more of the four following subtypes:
visual–auditory synesthesia, somatic–auditory synesthesia, gustatory–audi-
tory synesthesia, and visual–somatic synesthesia. Examples of the four sub-
types follows:
20 Journal of Humanistic Psychology 0(0)
(1) Visual–auditory synesthesia
I see every note, every sound and it was mostly like in three major primary
colors blue, green, and red most of the time and it was three dimensional . . .
almost like flax in the wind but ah almost maybe like northern lights.
I could see music . . . I don’t remember what it looked like, and I was thinking
I gotta remember what this looks like because it’s so beautiful, and the music
was wonderful because it anchors you and yet it propels you.
(2) Somatic–auditory synesthesia
my entire body was musical instrument for every sound, which was coming
through my head, and it eviscerated from top to bottom . . . I know what a grand
piano feels like when it is played.
(3) Gustatory–auditory synesthesia
I started tasting music . . . some of Indian instruments have very sharp cords,
those felt metallic in my mouth.
(4) Visual–somatic synesthesia
[one participant described simultaneously seeing a cloud and feeling] “the
dampness of the cloud” [against her arms; later, she described seeing a yellow
sun and feeling the] “heat of that yellow” [on her body].
Role of Music as Conveyor of Experience
A playlist of prerecorded music was played during the participants’ psi-
locybin session. The musical selections and the order of the playlist had
been arranged by study staff to complement the arc of intensity of the
effects of psilocybin. All 13 participants described how the music that
was played during their psilocybin session took on a central role in their
phenomenal experience. Participants described the music as a conduit,
vehicle, or carrier of their experience. For example, one participant
that music was really how everything was conveyed to me, it all came through
the music . . . like everything that I experienced did not really happen in the
English language, it kind of happened through the music, like the music was
the conduit for this experience to happen.
Belser et al. 21
Other participants said that they were “really living in the music,” or that
their experience matched “the rhythms within the music, ebbing and flow-
ing.” The music was sometimes described as a transformative substrate of the
experience. For example, one participant concluded: “the music was the sin-
gle thing that really transformed this from a hospital room or whatever it is
into an experience that was rich for this kind of exploration.”
Although all the participants described the centrality of music in their
experiences, five participants described a deeper, more significant experience
of the music as an agentic guide or ally that helped them navigate through
difficult experiences. These participants talked about the music as if it had
some agency: “The music was fantastic, actually—the music that they had. I
remember at one point, I thought, ‘It’s not the drug doing this—it’s the music.’
The music felt like it was what was making things happen.” These partici-
pants recounted working with the music as a “guide” or a “coauthor” of their
experiences. One participant, Caleb, marveled at his experience of “one great
musical journey following another.” He understood the music as a sort of
guide, each track providing “another turn in the road.” Caleb began to hear
the music as an ally, stating, “I almost worked with the music, like the music
felt like an ally.” Similarly, another participant described acting as the “coau-
thor” of “almost each and every sound.”
Four participants similarly described experiences in which their sense of
selfhood melded with the music being played. Allison commented,
I felt that I was part of the music and I was in the music, it was me. It was it just
me listening to music. I was the music. I was the drum, or the flute, or the
violin, and I was really part of that.
Of her experience, Augusta recalled: “Music is sort of like going in your ears
but it’s inside, and it’s outside, and you can’t tell the difference.”
Lasting Impact
Revised Life Priorities. All study participants reported experiencing benefits
related to their lifestyle and quality of life after the treatment sessions. Some
of the participants expressed coming to honor a different side of themselves,
a more still, emotional, or spiritual side that involved connecting to the sim-
plicity of the present moment:
The percentage of my life that I am able to be present in just a moment has
increased dramatically, and it’s really just been restored from almost nonexistent
to often existent . . . it is unique and monumental in a way.
22 Journal of Humanistic Psychology 0(0)
Participants described a shift in their life priorities away from the busy
demands of modern work life, to find a deeper or more authentic mode of
existence: “It has made me more aware that: I cannot just live for material
stuff and success.” These participants came to “remember” during their psi-
locybin session what to them was most important about life: “It felt whole
and complete and at peace. . . . We forget what’s really important; we get
carried away with work and making our money and paying our bills, and this
is just not what life is about.” Participants were compelled to reorient their
lives afterward in a way that continued to connect them to a similar place and
nourish that part of themselves. Augusta said:
I feel like a whole bunch of crap has been dumped off the surface. This stuff
that made my world shut down so much and made me look at the ground and
watch the clock numbers clicking by. There’s life and so many things going on,
just watching that tree over there blowing in the breeze, seeing people in the
street, and all the different people in vehicles rushing by! I just feel good about
being alive. . . . It’s always there; we just don’t notice, and I’m trying to notice
and not forget that I can see it at any time. I can hear it any time. It’s like waking
up in the most profound way, that this is really what life is, it’s really like this.
We’re just not noticing.
Here, Augusta shares how participating in the study has helped her “wake up
in the most profound way.” She also reported better practical outcomes, like
feeling less alone, having less “tunnel vision” and feeling more confident.
Lasting Changes to Sense of Identity. Similar to providing a shift toward what
is most meaningful in life, some participants reported that the psilocybin
experience afforded them greater confidence to put up boundaries against
various stressors in their life and the ability to overcome barriers that were
impeding life goals, allowing a greater sense of peace and freedom. When
one participant was asked, in what ways you feel the study has affected your
life since undergoing the sessions, she replied:
Just tremendously, tremendously. I am so much more able to do things that I
wanted to do, and didn’t feel I could, something always holding me back . . . I
really want to enjoy every minute. I want to enjoy being alive, and I knew that
before the study, but afterwards I became able to do it much more often. I have
found ways to make that happen.
This participant, who struggled with emotional/compulsive eating following
her cancer diagnosis, reported gaining confidence to commit to dietary goals
and a YMCA membership, losing 30 pounds as a result, an outcome she
attributed directly to her psilocybin session.
Belser et al. 23
Some participants described the sense of empowerment lasting well after
their psilocybin experience: “I am so much more able to do things that I
wanted do, and didn’t feel I could, um something always holding me back.”
Participants described other ways in which they connected to a new sense of
themselves as a result of the treatment. One participant concluded that after
her treatment, “for me everything has changed . . . I feel more contented and
happy about my place in the world in all the things I’m doing,” adding, “I’ve
really connected with a spiritual side in myself.” Another participant attested
to feeling a new kind of “resonance” with herself: “I feel more in touch with
who I really am—my real self, myself that’s connected to everyone and
everything.” One participant stated, “I kind of felt reborn in a way . . . I do
feel different. And I think that’s kind of what the next part of the process is,
to figure out what that means.”
Integration: Continued Struggle. Three participants continued to struggle with
the integration of their experiences after the study concluded. They report
that their lives have not been made miraculously easy or perfect. One reported
ambiguity regarding his experience, saying, “I still have to work on my prob-
lems myself . . . [the psilocybin experience] confirms certain thoughts and
hopes, ah, about who we are. Who I am. What’s important to me.” Another
participant reported persisting anxiety: “I still worry. It’s not like life is so
perfect now, but it’s better. It’s just better . . . I just don’t think that I feel as
sad as I used to feel.” A third participant reported prolonged difficulty follow-
ing her session, which required intensive support in integration psychother-
apy sessions with her therapists to process a childhood trauma. Of these three
participants who continued to struggle to integrate their experiences, all three
reported that they would repeat the psilocybin dosage session.
Desire to Repeat Psilocybin Experience
Study participants were only granted a single psilocybin administration session.
When asked if, given an opportunity, they would repeat the experience, 12 of the
13 participants reported that they would do so. The responses were overwhelm-
ingly positive: “I would definitely go through another experience, fully knowing
that it might be equally as much of a struggle and a battle.” Another replied,
“Yes. Absolutely. I would do it in a heartbeat. In addition, one participant
reported, “there are certain things I know now, I would, I would kind of stop
wondering around and would go through the particular experience and explore
them more.” What he described is typical, as seven of the participants described
a feeling that had they been familiar with the terrain of the psilocybin experi-
ence, they might have been able to go further with the experience. Other partici-
pants cited this phenomenon as an argument for repeat dosage sessions.
24 Journal of Humanistic Psychology 0(0)
Four participants stated that a given period of time would be optimal
before repeating the psilocybin experience. One participant said, “I’d do it
again, but not anytime soon,” a sentiment echoed by another participant, who
said, “I wish I could do it twice, not necessarily today or tomorrow but maybe
sometime in the future.” One participant thought a year would be an ideal
period of time. Only one participant, Adam, who at 21 years old was the
youngest participant in the study, was not eager to repeat the dosing session,
owing to the challenging nature of his experience. He suggests psilocybin is
vastly different from fun “party drugs” and that he would not repeat the expe-
rience given the amount of psychological “work” involved in processing the
vast amounts of information he learned about himself:
It is not fun, that is the thing. It is a hard experience; it is a very rich experience.
You have a lot of things to learn from it, but how much fun is learning, you
know? It is not that fun especially when you have to face some hard things . . .
you start putting everything together, and at the end you are a better person
because you know more. You know, but the experience itself is not fun, it is a
hard experience. It is like studying. It’s like going to school. It’s hard, you
Psilocybin-assisted psychotherapy is a promising combination intervention
for the treatment of psychological distress, psychiatric conditions, and “the
betterment of well people” (Bob Jesse, cited in Pollan, 2015). Despite the
resurgence in research using psilocybin in recent years, the psychological
mechanisms of action involved in psilocybin-assisted psychotherapy are not
yet well understood. Current theory regarding psychotherapeutic and phar-
macotherapeutic mechanisms of action posits that the occasion of a mystical
experience is the primary mediating factor leading to positive treatment out-
comes. While the construct of a “complete mystical experience,” for exam-
ple, as defined by exceeding a cutoff score on the Pahnke–Richards Mystical
Experience Questionnaire (Griffiths et al., 2006) has been shown to be one
mediator of positive outcomes in randomized controlled trials (Bogenschutz
et al., 2015; Griffiths et al., 2008; MacLean et al., 2011), the findings of this
study suggest a more complex topography. It is conceivable that a single
mediating factor is insufficient to account for multilevel phenomena that
carry cognitive, emotional, behavioral, psychodynamic, spiritual, existential,
and/or experiential components of significance.
The current study appears to be the first qualitative study of participant
experiences in psilocybin-assisted psychotherapy. The findings of this
Belser et al. 25
study suggest that there are important relational, bodily, affective, and
other aspects of participant experiences that may play critical roles. First,
participants universally described deeply meaningful attachments to
important family members and significant others. Relationships were
woven throughout participant narratives, with themes of forgiveness of
others, loved ones as spirit guides, the importance of narrating one’s expe-
rience with loved ones, and improved relationships posttreatment. In this
way, the psilocybin experience may be conceived as relationally embed-
ded. In many ways, this is unsurprising, given the important contributions
of attachment theory (Ainsworth, Blehar, Waters, & Wall, 2014; Bowlby,
1980, 2005), relational theory (Mitchell, 1988; Wachtel, 2010), and inter-
personal theory (Sullivan, 2013) to human development, which have yet to
be thoroughly integrated into psychedelic research paradigms. Nearly all
participants reported having an experience of love and joy, though these
exalted experiences arose primarily through a specific human relationship
with another person, whether it was a parent, child, or partner. As Anais
Nin (1971) once wrote, “The personal, if it is deep enough, becomes uni-
versal, mythical, symbolic” (p. 153). These findings indicate that a rela-
tional theoretical framework may have utility in assessing the importance
of transformed interpersonal and intrapsychic configurations occasioned
by psilocybin-assisted psychotherapy.
Second, the findings of the current study also suggest that embodiment,
and especially alterations or transfigurations of normally felt embodied
states, is a critical feature of participant experiences. Although participants
did describe discarnate phenomena, some of the most compelling accounts
spoke of bodily ejections of cancer and visions of accepting their bodies.
Participants described enhanced interoceptive awareness, somatic synes-
thetic experiences, and alterations to their sense of self as embodied beings.
Despite a trend toward embodiment as a broad interpretative framework in
the social and behavioral sciences (Csordas, 1994; Gibbs, 2005; Niedenthal,
Barsalou, Winkielman, Krauth-Gruber, & Ric, 2005), subjectively experi-
enced body states are not currently being assessed in clinical trials with psi-
locybin-assisted psychotherapy.
Third, slightly more than half of participants recounted acute reac-
tions of fear, confusion, panic, or paranoia during the psilocybin dosage
session. These were transient processes, and no serious adverse events
attributable to the study treatment occurred during the course of this
trial. The findings presented here suggest that transient periods of dis-
tress, even intense experiences of fear and panic, can be well tolerated by
study participants in a supportive therapeutic milieu. The development
of a trusting therapeutic alliance between the participant and the study
26 Journal of Humanistic Psychology 0(0)
therapists before the psilocybin administration session, followed by ade-
quate integration psychotherapy sessions afterward, provides a crucial
supportive context. While a straightforward review may deem experi-
ences of transient psychological distress as undesirable side effects, both
participants and the research team came to understand these difficult
experiences as part of a necessary and ultimately beneficial process. In
the midst of fear and dysphoria, participants described how they came to
surrender or “let go,” leading from a defensive posture of emotional or
psychological resistance to an accepting posture characterized by feel-
ings of relief, wholeness, freedom, and affirmation. Through a collabora-
tive interpretative process, our research team generated a variety of ways
of labeling these transient phenomena, including the following: the
shadow, the difficult struggle, the dark night of the soul, wrathful guard-
ians of the gates of the mandala, ego death, heaven and hell, and existen-
tial collapse. Each offered certain advantages but also brought with them
unwanted baggage from the psychological, theological, and psychedelic
traditions from which they were borrowed. Such periods of transient dis-
tress may serve as a necessary “turning point” in an unfolding process,
as feelings of fear, panic, and anxiety transmute into feelings of love, joy,
and forgiveness.
Fourth, these findings indicate that psilocybin occasions a rich and
complex range of human emotions. Participants described powerful and
healing catharses suggesting an emotional trajectory. Participant affects
have either not been assessed formally in clinical trials of psilocybin-
assisted psychotherapy, or the range of assessment is limited, as with the
use of visual analogue scales assessing feelings of fear, paranoia, and joy
(Turton et al., 2014). Our findings suggest that participants may emerge
from this treatment having experienced profound emotional depths and
expanded affective boundaries. Future research may evaluate cathartic
release and the depth and breadth of affect states occasioned during psilo-
cybin-assisted psychotherapy.
Fifth, participant accounts reveal a colorful, even fantastical range of com-
plex closed-eye visual phenomena. These visions are ideographically instan-
tiated within subjective processes. These complex visualizations are not
merely interesting scenes painted on the proscenium curtain of the theater of
the mind. Rather, among study participants, these visions served as principle
organizing motifs of subjective experience with multifold vectors (e.g.,
audiovisual, relational, autobiographical, spiritual, epistemological, ontolog-
ical). Such visions were often deeply coded with layers of meaning by
Belser et al. 27
Sixth, study participants described lasting impacts to their quality of life,
life priorities, and their sense of identity. During their psilocybin experiences,
many participants “remembered” aspects of themselves that had been forgot-
ten. They recovered a sense of what is most important and vital in their lives,
such as being present in the moment or being kind to other people. Participants
described feeling “reborn,” more expansive, more confident, more connected,
and more alive. They described a feeling of empowerment and being
“unstuck,” with resulting healthier behaviors. As two participants reported
significant weight loss, future research regarding the efficacy of psilocybin-
assisted psychotherapy as an intervention for obesity and eating disorders may
be warranted.
A number of limitations to this study should be noted. The interview
guide focused primarily on the participant experiences during the psilocy-
bin dosage session rather than the preparatory and integration psycho-
therapy sessions, which we see as essential components. The timing of the
interview poses certain concerns, as approximately half the sample were
interviewed within 1 week following their second psilocybin dosage ses-
sion, which allowed little time to review lasting impacts of their experi-
ences but afforded at least one integration psychotherapy session to help
consolidate memory and meaning. Conversely, as eight participants were
interviewed at approximately 1-year follow-up, the clarity of their recall
regarding specific phenomenal experiences a year earlier may have been
subject to distortion or clouding. Additionally, the current analysis does
not formally address participant–therapist interactions or the nature of
therapeutic action as experienced by the patients nor does it address the
variety of experiences related to cancer, death, and spirituality reported
by this cohort of cancer patients, which is documented in a subsequent
article (Swift et al., in press).
This is perhaps the first qualitative study to explore the subjective
inner texture of participant experiences of psilocybin-assisted psycho-
therapy. The findings of the study support the conclusion that psilocybin-
assisted psychotherapy is well accepted by participants and constitutes a
promising intervention for the treatment of existential and psychological
distress provoked by a cancer diagnosis. An IPA revealed a complex, mul-
tilevel set of processes. Participants experience this treatment as relation-
ally embedded, physically embodied, affect laden, deeply meaningful,
and biographically instantiated, with lasting impacts to their experience
of themselves and the world. Future research is warranted to attend to
these and other possible mediating factors in the design of clinical trials
to better articulate psychological mechanisms of action and maximize
therapeutic benefit.
28 Journal of Humanistic Psychology 0(0)
Declaration of Conflicting Interests
The author(s) declared the following potential conflicts of interest with respect to the
research, authorship, and/or publication of this article: T. Cody Swift is a board mem-
ber of the RiverStyx Foundation, which has made grants to the Heffter Research
Questions Included in the Semistructured Interview Guide.
How did you come to participate in the study?
What were your expectations?
What were you hoping for or looking for?
The treatment session
As a participant in this study, you have now participated in two treatment
sessions. According to your best guess, do you think you received the psilocybin
medication in the first or the second treatment session?
For the following questions, please consider the treatment session in which you
believe you received the psilocybin medication.
Can you describe in detail your experiences during this treatment session?
What perceptual changes did you experience (see, feel, hear)?
What internal changes did you experience?
What insights or new understandings did you gain?
What emotions arose during your experiences?
What memories arose during your experience?
How would you describe your experiences after the session ended and later that
Postsession questions
In what ways do you feel the study has affected your life since the sessions?
In what ways has do you feel your participation in the study has changed your
anxiety level?
How has the experience changed your perception of or attitude toward the
In your experience, how do you think the substance works to create such changes?
Other questions
Two study therapists were with you in the room during the treatment sessions.
What was your experience of the therapists and how did they affect your
Is there anything you wish had been different?
If given an opportunity, would you repeat the experience?
Is there anything else that you would like to share?
Belser et al. 29
The author(s) disclosed receipt of the following financial support for the research,
authorship, and/or publication of this article: This research was supported in part by
grants from the Heffter Research Institute.
Addy, P. H., Garcia-Romeu, A., Metzger, M., & Wade, J. (2015). The subjective
experience of acute, experimentally-induced Salvia divinorum inebriation.
Journal of Psychopharmacology, 29, 426-435.
Ainsworth, M. D. S., Blehar, M. C., Waters, E., & Wall, S. (2014). Patterns of attach-
ment: A psychological study of the strange situation. New York, NY: Psychology
Allen, J. W., & Arthur, J. (2005). Ethnomycology and distribution of the psilocybian
mushrooms. In R. Metzner (Ed.), Sacred mushroom of visions: Teonanacatl:
A sourcebook on the psilocybin mushroom (pp. 49-68). Rochester, VT: Inner
Beck, J., & Rosenbaum, M. (1994). Pursuit of ecstasy: The MDMA experience.
Albany: SUNY Press.
Bersani, F. S., Corazza, O., Albano, G., Valeriani, G., Santacroce, R., Posocco, F. B.
M., . . . Schifano, F. (2014). 25C-NBOMe: Preliminary data on pharmacology,
psychoactive effects, and toxicity of a new potent and dangerous hallucinogenic
drug. BioMed Research International, 2014. doi:10.1155/2014/734749
Bogenschutz, M. P., Forcehimes, A. A., Pommy, J. A., Wilcox, C. E., Barbosa, P. C.
R., & Strassman, R. J. (2015). Psilocybin-assisted treatment for alcohol depen-
dence: A proof-of-concept study. Journal of Psychopharmacology, 29, 289-299.
Bowlby, J. (1980). Attachment and loss (Vol. 3). New York, NY: Basic Books.
Bowlby, J. (2005). A secure base: Clinical applications of attachment theory. New
York, NY: Taylor & Francis.
Carhart-Harris, R. L., Bolstridge, M., Rucker, J., Day, C. M., Erritzoe, D., Kaelen, M.,
. . . Taylor, D. (2016). Psilocybin with psychological support for treatment-resis-
tant depression: An open-label feasibility study. Lancet Psychiatry, 3, 619-627.
Comis, M. A., & Noto, A. R. (2012). Reasons for not using ecstasy: A qualitative
study of non-users, ex-light users and ex-moderate users. BMC Public Health,
12(1), 353. doi:10.1186/1471-2458-12-353
Csordas, T. J. (1994). Embodiment and experience: The existential ground of culture
and self (Vol. 2). Cambridge, England: Cambridge University Press.
First, M. B. (2005). Structured clinical interview for DSM-IV-TR Axis I disorders:
Patient edition. New York, NY: Biometrics Research Department, Columbia
Friedman, H. (2006). The renewal of psychedelic research: Implications for humanis-
tic and transpersonal psychology. Humanistic Psychologist, 34, 39-58.
Garcia-Romeu, A., Himelstein, S. P., & Kaminker, J. (2015). Self-transcendent expe-
rience: A grounded theory study. Qualitative Research, 15, 633-654.
30 Journal of Humanistic Psychology 0(0)
Gasser, P., Kirchner, K., & Passie, T. (2014). LSD-assisted psychotherapy for anxi-
ety associated with a life-threatening disease: A qualitative study of acute and
sustained subjective effects. Journal of Psychopharmacology, 29, 57-68. doi:1
Gibbs, R. W., Jr. (2005). Embodiment and cognitive science. Cambridge, England:
Cambridge University Press.
Griffiths, R. R., Johnson, M. W., Carducci, M. A., Umbricht, A., Richards, W. A.,
Richards, B. D., . . . Klinedinst, M. A. (2016). Psilocybin produces substantial
and sustained decreases in depression and anxiety in patients with life-threaten-
ing cancer: A randomized double-blind trial. Journal of Psychopharmacology,
30, 1181-1197.
Griffiths, R. R., Johnson, M. W., Richards, W. A., Richards, B. D., McCann, U., &
Jesse, R. (2011). Psilocybin occasioned mystical-type experiences: Immediate
and persisting dose-related effects. Psychopharmacology, 218, 649-665.
Griffiths, R. R., Richards, W. A., Johnson, M. W., McCann, U. D., & Jesse, R.
(2008). Mystical-type experiences occasioned by psilocybin mediate the attribu-
tion of personal meaning and spiritual significance 14 months later. Journal of
Psychopharmacology, 22, 621-632.
Griffiths, R. R., Richards, W. A., McCann, U., & Jesse, R. (2006). Psilocybin can
occasion mystical-type experiences having substantial and sustained personal
meaning and spiritual significance. Psychopharmacology, 187, 268-283.
Grob, C. S., Danforth, A. L., Chopra, G. S., Hagerty, M., McKay, C. R., Halberstadt,
A. L., & Greer, G. R. (2011). Pilot study of psilocybin treatment for anxiety
in patients with advanced-stage cancer. Archives of General Psychiatry, 68(1),
Hill, C. E., Knox, S., Thompson, B. J., Williams, E. N., Hess, S. A., & Ladany,
N. (2005). Consensual qualitative research: An update. Journal of Counseling
Psychology, 52, 196-205.
Miles, M. B., & Huberman, A. M. (1994). Qualitative data analysis: An expanded
sourcebook (2nd ed.). Thousand Oaks, CA: Sage.
Kjellgren, A., & Soussan, C. (2011). Heaven and hell: A phenomenological study of
recreational use of 4-HO-MET in Sweden. Journal of Psychoactive Drugs, 43,
Loizaga-Velder, A., & Verres, R. (2014). Therapeutic effects of ritual ayahuasca
use in the treatment of substance dependence: Qualitative results. Journal of
Psychoactive Drugs, 46, 63-72.
MacLean, K. A., Johnson, M. W., & Griffiths, R. R. (2011). Mystical experiences
occasioned by the hallucinogen psilocybin lead to increases in the personality
domain of openness. Journal of Psychopharmacology, 25, 1453-1461.
McAdams, D. (1999). Personal narratives and the life story. In L. Pervin, & O. John
(Eds.), Handbook of personality: Theory and research (2nd ed., pp. 478-500).
New York: Guilford Press.
Mitchell, S. A. (1988). Relational concepts in psychoanalysis. Cambridge, MA:
Harvard University Press.
Muhr, T. (2014). ATLAS.ti (Version 7.5.4) [Computer software]. Berlin, Germany:
Scientific Software Development.
Belser et al. 31
Niedenthal, P. M., Barsalou, L. W., Winkielman, P., Krauth-Gruber, S., & Ric, F.
(2005). Embodiment in attitudes, social perception, and emotion. Personality and
Social Psychology Review, 9, 184-211.
Nin, A. (1971). The Diary of Anais Nin Volume 4: 1944-1947 (G. Stuhlmann, Ed.).
New York, NY: Harcourt Brace Jovanovich.
Noorani, T., Garcia-Romeu, A., Griffiths, R. R., & Johnson, M. W. (2015, May).
Identifying perceived mechanisms of change in the use of psilocybin to occasion
smoking cessation: Possibilities and challenges. Presentation at the Society for
Qualitative Inquiry in Psychology (SQIP) 2015 Annual Conference Symposium,
the Graduate Center, City University of New York, New York.
Pahnke, W. N. (1969). Psychedelic drugs and mystical experience. International
Psychiatry Clinics, 5(4), 149-162.
Passie, T. (2012). Healing with entactogens. Santa Cruz, CA: MAPS.
Pennay, A., & Moore, D. (2010). Exploring the micro-politics of normalisation:
Narratives of pleasure, self-control and desire in a sample of young Australian
“party drug” users. Addiction Research & Theory, 18, 557-571.
Pollan, M. (2015, February 9). The trip treatment. The New Yorker. Retrieved from
Presser-Felder, A. (2013). Treating substance dependencies with psychoactives: A
theoretical and qualitative empirical study on therapeutic uses of ayahuasca
(Doctoral dissertation). Institute for Medical Psychology, Ruprecht-Karls-
Universität Heidelberg, Heidelberg, Germany.
Ross, S., Bossis, A., Guss, J., Agin-Liebes, G., Malone, T., Cohen, B., . . . Schmidt, B.
(2016). Rapid and sustained symptom reduction following psilocybin treatment
for anxiety and depression in patients with life-threatening cancer: A randomized
controlled trial. Journal of Psychopharmacology, 30, 1165-1180.
Schweiger, D. M., Sandberg, W. R., & Ragan, J. W. (1986). Group approaches for
improving strategic decision making: A comparative analysis of dialectical
inquiry, devil’s advocacy, and consensus. Academy of Management Journal, 29,
Shanon, B. (2002). The antipodes of the mind: Charting the phenomenology of the
ayahuasca experience. Oxford, England: Oxford University Press.
Singer, E. O., & Schensul, J. J. (2011). Negotiating ecstasy risk, reward, and control:
A qualitative analysis of drug management patterns among ecstasy-using urban
young adults. Substance Use & Misuse, 46, 1675-1689.
Smith, J. A., Flowers, P., & Larkin, M. (2009). Interpretative phenomenological anal-
ysis: Theory, method and research. Thousand Oaks, CA: Sage.
Stamets, P. (1996). Psilocybin mushrooms of the world: An identification guide.
Berkeley, CA: Ten Speed.
Studerus, E., Kometer, M., Hasler, F., & Vollenweider, F. X. (2011). Acute, subacute
and long-term subjective effects of psilocybin in healthy humans: A pooled anal-
ysis of experimental studies. Journal of Psychopharmacology, 25, 1434-1452.
Sullivan, H. S. (2013). The interpersonal theory of psychiatry. New York, NY:
Swift, T. C., Belser, A. B., Agin-Liebes, G., Terrana, S., Devenot, N., Friedman,
H. L., . . . Ross, S. (in press). Cancer at the dinner table: Experiences of
32 Journal of Humanistic Psychology 0(0)
psilocybin-assisted psychotherapy for the treatment of cancer-related psycho-
logical distress. Journal of Humanistic Psychology.
Turton, S., Nutt, D. J., & Carhart-Harris, R. L. (2014). A qualitative report on the
subjective experience of intravenous psilocybin administered in an fMRI envi-
ronment. Current Drug Abuse Reviews, 7, 117-127.
Wachtel, P. L. (2010). Relational theory and the practice of psychotherapy. New
York, NY: Guilford Press.
Wasson, R. G. (1980). The wondrous mushroom: Mycolatry in Mesoamerica. New
York, NY: McGraw-Hill.
Yaden, D. B., Le Nguyen, K. D., Kern, M. L., Belser, A. B., Eichstaedt, J. C., Iwry,
J., . . . Newberg, A. B. (2016). Of roots and fruits: A comparison of psychedelic
and non-psychedelic mystical experiences. Journal of Humanistic Psychology,
1, 1-16.
Author Biographies
Alexander B. Belser, MPhil, is a fellow and adjunct
instructor in the Department of Applied Psychology at
New York University (NYU). He cofounded the NYU
Psychedelic Research Group in 2006. He is an investigator
of a qualitative study exploring how patients with cancer
experience psilocybin-assisted psychotherapy. He serves
as a scientific collaborator for the NYU Psilocybin Alcohol
Dependence Qualitative Study, a study investigating psilo-
cybin treatment for alcohol addiction. He is also helping
conduct a qualitative study of religious leaders who are
administered psilocybin. He graduated from Georgetown University, and pursued
graduate studies at Cambridge University, NYU, and Columbia University. He is a
member of the Research Advisory Board of Compass Pathways, a medical research
foundation that supports innovation in mental health through translational research.
He currently works at Mount Sinai Beth Israel Hospital, and lives in Brooklyn, New
York. His website is
Gabrielle Agin-Liebes is completing her training toward
a PhD in clinical psychology at Palo Alto University
(PAU) under the joint mentorship of Matthew J. Cordova,
PhD, and Josef Ruzek, PhD. She is a member of the PAU
Early Intervention Clinic lab, which provides and evalu-
ates evidence-based treatments to prevent trauma-related
problems in recently traumatized individuals. As part of
this research laboratory, she is examining the effects of
self-compassion on trauma-related guilt cognitions and
shame. She is also a practicum therapist at the Gronowski
Center, a community mental health clinic, and coleads an empirically supported medi-
tation group at Kara Grief Support Center in Palo Alto.
Belser et al. 33
T. Cody Swift, MA, MFTI, received his degree in exis-
tential–phenomenological psychology from Seattle
University and is currently perusing clinical licensure
in California. He has worked as a guide at Johns
Hopkins University in the psilocybin cancer–anxiety
study, and is currently conducting qualitative research
into the nature of healing with psychedelics in a clinical
context, with MDMA and psilocybin. He is also a current director of the Riverstyx
Foundation which has been dedicated to advancing opportunities for psychological
growth and healing in the areas of end-of-life care, addiction recovery, and the crimi-
nal justice system.
Sara Terrana is a doctoral student at UCLA–Luskin,
School of Public Affairs in the Department of Social
Welfare. Her research interests are in nonprofit human
service organizations, founders of such organizations,
and neighborhoods of concentrated disadvantage; she
also specializes in qualitative methodology and
advanced CAQDAS (computer-assisted qualitative
data analysis software) technologies.
Neşe Devenot, PhD, graduated from the University of
Pennsylvania in 2015 with a doctorate in comparative
literature, and she currently serves as Andrew W.
Mellon Postdoctoral Fellow in Digital Humanities at
the University of Puget Sound in Tacoma, WA. She
was a 2015-2016 Research Fellow at the New York
Public Library’s Timothy Leary Papers, and she was
awarded Best Humanities Publication in Psychedelic
Studies from Breaking Convention in 2016. Her research explores the function of
metaphor and other literary devices in verbal accounts of psychedelic experiences.
Harris L. Friedman, PhD, is retired research professor of
psychology at University of Florida, and is professor emeri-
tus of Humanistic and Transpersonal Psychology at
Saybrook University and Distinguished Professor of
Integral and Transpersonal Psychology at the California
Institute of Integral Studies. He now teaches at Goddard
College, supervises dissertations at several universities, and
also practices as a clinical psychologist and organizational
consultant. He has written extensively on transpersonal
assessment and psychotherapy, as well as on culture and
change. He is a prolific author with over 200 professional
publications, and his recent books, with other authors/
34 Journal of Humanistic Psychology 0(0)
editors, include Transcultural Competence (American Psychological Association,
2015), The Praeger Handbook of Social Justice and Psychology (three volumes;
2014), and The Wiley-Blackwell Handbook of Transpersonal Psychology (2013). He
serves as the associate editor of Humanistic Psychologist and the senior editor of the
International Journal of Transpersonal Studies.
Jeffrey Guss, MD, is a psychiatrist, psychoanalyst, and
researcher with specializations in psychoanalytic therapy
and the treatment of substance use disorders. He is
coprincipal investigator and director of Therapist
Training for the NYU School of Medicine’s study on
psilocybin-assisted psychotherapy in the treatment of
cancer-related existential distress. He is interested in the
integration of psychedelic therapies with contemporary
psychoanalytic theory and has published in Studies in
Gender and Sexuality and Psychoanalysis, Culture &
Society. He is an instructor and mentor with the California
Institute of Integral Studies’ Center for Psychedelic
Therapies and maintains a full-time private practice.
Anthony Bossis, PhD, is a clinical assistant professor of
psychiatry at New York University School of Medicine
and a founding member of the NYU Psilocybin Research
Group, which in 2009 began FDA-approved scientific
research into the therapeutic efficacy of psilocybin, a
naturally occurring psychedelic compound found in spe-
cific species of mushrooms. He was director of Palliative
Care Research, coprincipal investigator, and psilocybin
session guide for the NYU clinical trial investigating the
efficacy of a psilocybin-generated mystical experience on the existential and psycho-
spiritual distress in persons with cancer. Subjective features of a mystical experience
include unity, sacredness, transcendence, and a greater connection to deeply felt posi-
tive emotions including that of love. The study results were published in the Journal of
Psychopharmacology in December 2016. He is a clinical supervisor of psychotherapy
training and cofounder and former codirector of the Palliative Care Service at Bellevue
Hospital. He has a long-standing interest in comparative religion, consciousness
research, and the interface of psychology and spirituality. He maintains a private con-
sulting and psychotherapy practice in New York City.
Stephen Ross, MD, is associate professor of Psychiatry
and Child and Adolescent Psychiatry at the New York
University (NYU) School of Medicine and associate
professor of oral and maxillofacial pathology, radiology,
and medicine at the NYU College of Dentistry. He is the
director of the Division of Alcoholism and Drug Abuse
in the Psychiatry Department at Bellevue Hospital
Belser et al. 35
Center, director of Addiction Psychiatry at NYU Langone Medical Center/Tisch
Hospital, and the director of the NYU Addiction Fellowship. He directs an NIH-funded
Addictive Disorders Laboratory at Bellevue Hospital Center and is the director of the
NYU Psychedelic Research Group. He researches the therapeutic application of hallu-
cinogen treatment models to treat psychiatric and addictive disorders. He is an expert in
psycho-oncology and is studying novel pharmacologic–psychosocial approaches to
treating psychological distress associated with advanced or terminal cancer. He is the
principal investigator (PI) of the NYU Psilocybin Cancer Project (a recently completed
FDA phase II RCT studying the efficacy of psilocybin-assisted psychotherapy in
patients with life-threatening cancer and psychological/existential distress), PI of a con-
trolled trial administering psilocybin to religious professionals, and co-PI of a controlled
trial assessing psilocybin-assisted psychotherapy in patients with alcoholism. He
receives his research funding from the National Institute on Drug Abuse (NIDA), the
NYU School of Medicine and the Heffter Research Institute.
...  Loneliness correlates with depression, anxiety, poor health behaviors, sleep problems, stress, and premature mortality (Fried et al., 2020 PSILOCYBIN  Psilocybin, a naturally occurring serotonergic compound found in over 180 species of mushrooms, produces spiritual and mystical experiences that elicit meaning-making and feelings of connectedness, a key variable in psychological wellbeing (Belser, 2017). ...
...  Psilocybin evokes mystical experiences leading to renewed meaning-making which includes relational connectedness, increased emotional range, meaningful visual experiences, renewed wisdom, renewed life priorities, and feelings of joy, bliss, and love (Belser et al., 2017). ...
...  Psilocybin may transition feelings of separateness to interconnectedness, leading to lasting changes to an individual's sense of identity (Belser et al., 2017). ...
Full-text available
Approximately one-third of all adults globally report feelings of loneliness (Luchetti et al., 2020; Preece et al., 2021). International research has shown that loneliness has increased in the past 40 years, doubling from 20 to 40 percent since 1980 (Mate & Mate, 2022). Loneliness, the subjective feeling of inadequate meaningful connection (Fried et al., 2020), impacts individuals and communities, affecting wellbeing (Barreto et al., 2021). Globally, a growing concern about rates and consequences of loneliness elicited the appointment of the first minister for loneliness in the UK and a committee at the US National Academies of Sciences, Engineering, and Medicine (Fried et al., 2020). The loneliness epidemic represents a public health crisis, and serves as a primary factor underlying many psychopathologies (Preece et al., 2021). Loneliness correlates with depression, anxiety, poor health behaviors, sleep problems, stress, and premature mortality (Fried et al., 2020). Lonely people crave connectedness (Saporta et al., 2022). Psilocybin, a naturally occurring serotonergic compound found in over 180 species of mushrooms, produces spiritual and mystical experiences that elicit meaning-making and feelings of connectedness, a key variable in psychological wellbeing (Belser, 2017). Psilocybin evokes mystical experiences leading to renewed meaning-making which includes relational connectedness, increased emotional range, meaningful visual experiences, renewed wisdom, renewed life priorities, and feelings of joy, bliss, and love (Belser et al., 2017). Psilocybin may transition feelings of separateness to interconnectedness, leading to lasting changes to an individual’s sense of identity (Belser et al., 2017). The primary factor underlying many psychopathologies and mental health disparities centers on the lack of connection or the feeling of disconnection (Carhart-Harris et al., 2018). The impact of psilocybin on feelings of connectedness may indicate the usefulness of the substance to combat loneliness (Carhart-Harris et al., 2018). Research subjects who used psilocybin reported a renewed sense of connection or connectedness, specifically to self, others, and the world in general (Carhart-Harris et al., 2018; Watts et al., 2017). The potential of psilocybin to directly combat the loneliness epidemic has attracted the attention on numerous corporations, which now construct industry around the substance. Before this industry is further developed, clearer understanding of the impacts on Indigenous people is needed. Indigenous communities have used psilocybin in sacred practice for thousands of years. Legalizing psilocybin may deny those communities the ability to conduct psilocybin related sacrament, which disenfranchises marginalized communities by colonialists. While psilocybin may prove useful for combatting loneliness, it should not come at a cost to Indigenous communities.
... Psilocybin-assisted psychotherapy may be well suited to bridge the gap between current body image strategies, which typically target the cognitive and behavioural components of BID, while the perceptual aspects are rarely or inadequately addressed (52) (34). Psilocybin has been reported to facilitate an embodied experience (53). At a fundamental level, embodiment describes the experience of inhabiting one's body in a way that allows attunement with the internal (physiological, emotional, and cognitive) aspects of self as they interact with the physical environment (American Psychological Association, 2015), although Cook-Cottone (54) extends and sharpens the concept of embodiment to include the interpersonal, social, cultural, and existential experience. ...
... Some preliminary research provides accounts of how psilocybin may function at a perceptual level. For example, in a qualitative study of 13 adults who received psilocybin-assisted psychotherapy to treat clinical anxiety associated with advanced cancer, many participants reported profound somatic experiences of psilocybin working with their body or altering their embodied relationship with the illness, including enhanced interoception and bodily self-acceptance (53). ...
Full-text available
Background: Body Image Disturbance (BID) is the distorted experience of one’s body. BID presents a risk for the onset, maintenance and relapse of body dysmorphic disorder and eating disorders, including anorexia nervosa (AN). Current treatments tend to focus on the cognitive and behavioural aspects while overlooking the perceptual symptoms and BID frequently persists beyond physical recovery. Psilocybin-assisted psychotherapy (PAP) may bridge the gap in current BID treatments by addressing perceptual and affective symptoms. This study sought to inform the development of a PAP treatment manual for BID in AN, through a co-design process informed by individuals with lived/living experience of AN. Methods: A Lived Experience Panel (LEAP) comprising six adult women who had a lived or living experience of AN and associated BID were presented with the proposed treatment protocol, including therapeutic interventions, and invited to provide feedback. An experiential, relativist framework informed reflexive thematic analysis of the LEAP data. Results: Reflexive thematic analysis of the LEAP data identified three central themes: enduring uncertainty; managing internal experience, and ambivalence in recovery. The LEAP also proposed strategies to address the challenges they identified and enhance the treatment manual more broadly. Conclusions: The LEAP identified challenges associated with intolerance of uncertainty, harm avoidance, alexithymia, and interoceptive impairment. The LEAP provided feedback that directly informed adaptations to the PAP treatment manual, including graduated interventions, the inclusion of nominated supports, and comprehensive psychoeducation for participants and their supports. Accordingly, a PAP treatment manual to treat BID for individuals with AN has been developed through lived experience co-design.
... (2) connection (interconnectedness, oneness, reconnection, compassion and part of a wider universe); (3) transformation (freed from past, alterations to a sense of self, more control, change of perception). Several studies have also identified the psilocybin experience as involving a spiritual awakening (Carhart-Harris & Nutt, 2010;Corneille & Luke, 2021;Griffiths et al., 2008), and extreme emotional responses (Al-Naggar et al., 2021;Belser et al., 2017;Pedersen et al., 2021). Another study has identified a reduction in attachment anxiety as a feature of the psilocybin experience (Stauffer et al., 2021). ...
This perspective paper explores the choice of psychotherapy for psilocybin-assisted psychotherapy for treatment-resistant depression. There is evidence to support the use of some psychotherapies in treating 'treatment-resistant' depression, and emerging evidence for the efficacy of psilocybin. The next step which is the focus of this paper is to identify psychotherapies that are both effective and congruent with the psilocybin experience. The evidence for the efficacy of the psychotherapies is drawn from a Cochrane review and the analysis of their congruence with the psilocybin experience is drawn from a qualitative meta-synthesis of the experience of psilocybin. The paper will examine whether three one-to-one psychotherapies identified as effective in the treatment of treatment-resistant depression are compatible with the psilocybin experience. Each psychotherapy will be examined in relation to its congruence with the qualitative evidence that suggests the choice of psychotherapy needs to give priority to the subjective experience, facilitate emotional processing, support connectedness with others, acceptance of the self as emotional and support change based on the person's insights into their relationships with others and the world in which they live. We conclude that interpersonal psychotherapy and intensive short-term dynamic psychotherapy align with that experience, although others are currently being trialled.
... IPA typically holds an idiographic component which allows the researcher to look for the meaning behind an individual's experience by interpreting the data through a psychological lens (19). Also, IPA is one of the primary methodologies used in similar clinical trials focusing on MDMA and alternate compounds (14,20,21). ...
Full-text available
Post-traumatic stress disorder (PTSD) is a prevalent psychiatric condition that significantly impacts daily functioning in patients but lacks adequate treatment options. 3,4-methylenedioxymethamphetamine (MDMA) as an adjunct to psychotherapy for the treatment of PTSD has been studied increasingly for the last two decades and has shown promising results through quantitative data. However, few qualitative studies have been conducted to investigate patients’ experiences who participate in these trials. This study intends to complement and clarify the quantitative findings resulting from a Phase-II clinical trial for assessing the safety and efficacy of MDMA-assisted psychotherapy for PTSD by using a qualitative approach based on available material of 4 recorded and transcripted integrative sessions per participant. An Interpretative Phenomenological Analysis (IPA) was conducted for 7 participants who met criteria for severe PTSD to develop a deeper understanding of the treatment and its efficacy. Analysis results provided real-life statements from participants that reflect perceived mechanisms of change and showed to what extent their proposed working mechanisms integrate into daily life.
Psychedelic substances have a long history of use in traditional healing and religious ceremonies worldwide and are increasingly being investigated for their possible therapeutic usage. However, there is still a lack of consensus regarding how best to characterize the psychological effects of psychedelics and how they bring about the positive therapeutic outcomes observed in clinical studies. The aim of this article is to review available evidence from quantitative and qualitative studies on psychedelic-assisted therapy, as well as neurobiological studies, in relation to the hypothesis that psychedelics facilitate the emergence of emotionally charged unconscious material, originally proposed by pioneering psychedelics researcher Stanislav Grof. The reviewed process studies of therapeutic mechanisms in psychedelic-assisted therapy and qualitative studies of treatment participants clearly indicate that the psychedelic experience is associated with the subjective experience of having increased access to and awareness of emotions, memories, and perceptions that are normally avoided or outside of conscious awareness. Brain-imaging studies point to several different neurobiological effects of psychedelics that might be related to these subjective psychological experiences. Available evidence also indicates that this process might constitute an important therapeutic mechanism in psychedelic-assisted therapy, worthy of further investigation.
Full-text available
Reports of psychedelic experiences may contain similarities and differences across cultural contexts, but most current characterizations and quantifications of psychedelic experiences come from Western medical and naturalistic settings. In this article, we begin with a brief history of the diversity of psychedelic use in non-Western settings. We then compare and contrast accounts of psychedelic experiences within and beyond Western, educated, industrialized, rich, and democratic (WEIRD) contexts. We focus on specific reports of direct testimony of the acute subjective effects of psychedelics experienced across these contexts. We compare themes from each of these various contexts, with special emphasis on psychometric measures such as the mystical experiences questionnaire (MEQ), the five-dimensional altered states of consciousness (5D-ASC) scale, the Survey of God Encounters, and the Survey of Entity Encounters, the Challenging Experiences Questionnaire, and the Inventory of Nonordinary Experiences (INOE). Finally, we offer recommendations for future research to quantify these similarities and differences across cultures to assess them empirically in the future.
Metaphors, analogies, and similes commonly appear in narratives of drinking the potent psychedelic "ayahuasca", presenting an intriguing transcultural pattern. Based upon survey and field research at an ayahuasca healing center in Pucallpa, Peru, the article investigates conceptual metaphors in narratives of ayahuasca experiences made by the visiting international guests. Bodily metaphors and visionary analogies frequently appear in narrative plots where they can express the reappraisal, overcoming, and sometimes emboldening of symptoms diagnosed by psychiatry. Moving beyond the literal-figurative divide, the article explores the intrinsic "metaphoricity" of psychedelic experiences and advocates for a literacy of conceptual metaphors regarding both clinical and non-clinical psychedelic narratives. Developing this literacy can broaden approaches in psychedelic psychiatry that analyze and treat syndromes and disorders, while also being applicable to social science and humanities research that examine psychoactive drug use beyond medical frameworks.
Full-text available
A rapid review synthesizing published research on the possible therapeutic applications of psychedelics.
Full-text available
i Abstract Psilocybin is a psychedelic compound of interest to clinicians, researchers and the general public for its unique effects on perception, cognition and emotion. Fifteen years of clinical trials, reviewed here using the scoping review method of knowledge synthesis , provide evidence for the safety and therapeutic efficacy of psilocybin when combined with psychological supports. A similar review of more than 50 years of research on non-human animals shows the safety of psilocybin and demonstrates persisting positive effects of psilocybin on self-regulation. To provide context to these scoping reviews, I conducted a detailed literature review and a separate narrative review on the neuroscience of psilocybin, with a marked interest in the dynamics of neuroplasticity and how habits of self-regulation are formed, revised and updated. While my working hypothesis considered mystical states as the mechanism of therapeutic action underlying psilocybin’s apparent benefits, the evidence was stronger to support a revised hypothesis: that psilocybin improves self-regulation. It does so by disrupting habit, potentiating new learning and promoting improvements to health behaviours. I offer here a novel contribution to the literature: a time-based Transition State Model of Psychedelic Effect which views psilocybin as a catalyst to improved flexibility of thought and behaviour. Psilocybin appears to attenuate or loosen the effects of past conditioning which appear as habits and which have become hard-wired into brain networks. This learning model heavily weights the activities undertaken in the days and weeks following psilocybin administration, providing a basis for psilocybin-assisted therapies to leverage this critical period for improvements to health behaviours.
As psychedelic compounds gain traction in psychiatry, there is a need to consider the active mechanism to explain the effect observed in randomized clinical trials. Traditionally, biological psychiatry has asked how compounds affect the causal pathways of illness to reduce symptoms and therefore focus on analysis of the pharmacologic properties. In psychedelic-assisted psychotherapy (PAP), there is debate about whether ingestion of the psychedelic alone is thought to be responsible for the clinical outcome. A question arises how the medication and psychotherapeutic intervention together might lead to neurobiological changes that underlie recovery from illness such as post-traumatic stress disorder (PTSD). This paper offers a framework for investigating the neurobiological basis of PAP by extrapolating from models used to explain how a pharmacologic intervention might create an optimal brain state during which environmental input has enduring effects. Specifically, there are developmental "critical" periods (CP) with exquisite sensitivity to environmental input; the biological characteristics are largely unknown. We discuss a hypothesis that psychedelics may remove the brakes on adult neuroplasticity, inducing a state similar to that of neurodevelopment. In the visual system, progress has been made both in identifying the biological conditions which distinguishes the CP and in manipulating the active ingredients with the idea that we might pharmacologically reopen a critical period in adulthood. We highlight ocular dominance plasticity (ODP) in the visual system as a model for characterizing CP in limbic systems relevant to psychiatry. A CP framework may help to integrate the neuroscientific inquiry with the influence of the environment both in development and in PAP. Appeared originally in Front Neurosci 2021; 15:710004.
Full-text available
Cancer patients often develop chronic, clinically significant symptoms of depression and anxiety. Previous studies suggest that psilocybin may decrease depression and anxiety in cancer patients. The effects of psilocybin were studied in 51 cancer patients with life-threatening diagnoses and symptoms of depression and/or anxiety. This randomized, double-blind, cross-over trial investigated the effects of a very low (placebo-like) dose (1 or 3 mg/70 kg) vs. a high dose (22 or 30 mg/70 kg) of psilocybin administered in counterbalanced sequence with 5 weeks between sessions and a 6-month follow-up. Instructions to participants and staff minimized expectancy effects. Participants, staff, and community observers rated participant moods, attitudes, and behaviors throughout the study. High-dose psilocybin produced large decreases in clinician- and self-rated measures of depressed mood and anxiety, along with increases in quality of life, life meaning, and optimism, and decreases in death anxiety. At 6-month follow-up, these changes were sustained, with about 80% of participants continuing to show clinically significant decreases in depressed mood and anxiety. Participants attributed improvements in attitudes about life/self, mood, relationships, and spirituality to the high-dose experience, with >80% endorsing moderately or greater increased well-being/life satisfaction. Community observer ratings showed corresponding changes. Mystical-type psilocybin experience on session day mediated the effect of psilocybin dose on therapeutic outcomes. Trial Registration identifier: NCT00465595
Full-text available
Background: Clinically significant anxiety and depression are common in patients with cancer, and are associated with poor psychiatric and medical outcomes. Historical and recent research suggests a role for psilocybin to treat cancer-related anxiety and depression. Methods: In this double-blind, placebo-controlled, crossover trial, 29 patients with cancer-related anxiety and depression were randomly assigned and received treatment with single-dose psilocybin (0.3 mg/kg) or niacin, both in conjunction with psychotherapy. The primary outcomes were anxiety and depression assessed between groups prior to the crossover at 7 weeks. Results: Prior to the crossover, psilocybin produced immediate, substantial, and sustained improvements in anxiety and depression and led to decreases in cancer-related demoralization and hopelessness, improved spiritual wellbeing, and increased quality of life. At the 6.5-month follow-up, psilocybin was associated with enduring anxiolytic and anti-depressant effects (approximately 60-80% of participants continued with clinically significant reductions in depression or anxiety), sustained benefits in existential distress and quality of life, as well as improved attitudes towards death. The psilocybin-induced mystical experience mediated the therapeutic effect of psilocybin on anxiety and depression. Conclusions: In conjunction with psychotherapy, single moderate-dose psilocybin produced rapid, robust and enduring anxiolytic and anti-depressant effects in patients with cancer-related psychological distress. Trial registration: Identifier: NCT00957359.
Full-text available
Experiences of profound existential or spiritual significance can be triggered reliably through psychopharmacological means using psychedelic substances. However, little is known about the benefits of religious, spiritual, or mystical experiences (RSMEs) prompted by psychedelic substances, as compared with those that occur through other means. In this study, 739 self-selected participants reported the psychological impact of their RSMEs and indicated whether they were induced by a psychedelic substance. Experiences induced by psychedelic substances were rated as more intensely mystical (d = .75, p < .001), resulted in a reduced fear of death (d = .21, p < .01), increased sense of purpose (d = .18, p < .05), and increased spirituality (d = .28, p < .001) as compared with nonpsychedelically triggered RSMEs. These results remained significant in an expanded model controlling for gender, education, socioeconomic status, and religious affiliation. These findings lend support to the growing consensus that RSMEs induced with psychedelic substances are genuinely mystical and generally positive in outcome.
Full-text available
Background: Psilocybin is a serotonin receptor agonist that occurs naturally in some mushroom species. Recent studies have assessed the therapeutic potential of psilocybin for various conditions, including end-of-life anxiety, obsessive-compulsive disorder, and smoking and alcohol dependence, with promising preliminary results. Here, we aimed to investigate the feasibility, safety, and efficacy of psilocybin in patients with unipolar treatment-resistant depression. Methods: In this open-label feasibility trial, 12 patients (six men, six women) with moderate-to-severe, unipolar, treatment-resistant major depression received two oral doses of psilocybin (10 mg and 25 mg, 7 days apart) in a supportive setting. There was no control group. Psychological support was provided before, during, and after each session. The primary outcome measure for feasibility was patient-reported intensity of psilocybin's effects. Patients were monitored for adverse reactions during the dosing sessions and subsequent clinic and remote follow-up. Depressive symptoms were assessed with standard assessments from 1 week to 3 months after treatment, with the 16-item Quick Inventory of Depressive Symptoms (QIDS) serving as the primary efficacy outcome. This trial is registered with ISRCTN, number ISRCTN14426797. Findings: Psilocybin's acute psychedelic effects typically became detectable 30-60 min after dosing, peaked 2-3 h after dosing, and subsided to negligible levels at least 6 h after dosing. Mean self-rated intensity (on a 0-1 scale) was 0·51 (SD 0·36) for the low-dose session and 0·75 (SD 0·27) for the high-dose session. Psilocybin was well tolerated by all of the patients, and no serious or unexpected adverse events occurred. The adverse reactions we noted were transient anxiety during drug onset (all patients), transient confusion or thought disorder (nine patients), mild and transient nausea (four patients), and transient headache (four patients). Relative to baseline, depressive symptoms were markedly reduced 1 week (mean QIDS difference -11·8, 95% CI -9·15 to -14·35, p=0·002, Hedges' g=3·1) and 3 months (-9·2, 95% CI -5·69 to -12·71, p=0·003, Hedges' g=2) after high-dose treatment. Marked and sustained improvements in anxiety and anhedonia were also noted. Interpretation: This study provides preliminary support for the safety and efficacy of psilocybin for treatment-resistant depression and motivates further trials, with more rigorous designs, to better examine the therapeutic potential of this approach. Funding: Medical Research Council.
Recent randomized controlled trials of psilocybin-assisted psychotherapy for patients with cancer suggest that this treatment results in large-magnitude reductions in anxiety and depression as well as improvements in attitudes toward disease progression and death, quality of life, and spirituality. To better understand these findings, we sought to identify psychological mechanisms of action using qualitative methods to study patient experiences in psilocybin-assisted psychotherapy. Semistructured interviews were conducted with 13 adult participants with clinically elevated anxiety associated with a cancer diagnosis who received a single dose of psilocybin under close clinical supervision. Transcribed interviews were analyzed using interpretative phenomenological analysis, which resulted in 10 themes, focused specifically on cancer, death and dying, and healing narratives. Participants spoke to the anxiety and trauma related to cancer, and perceived lack of available emotional support. Participants described the immersive and distressing effects of the psilocybin session, which led to reconciliations with death, an acknowledgment of cancer’s place in life, and emotional uncoupling from cancer. Participants made spiritual or religious interpretations of their experience, and the psilocybin therapy helped facilitate a felt reconnection to life, a reclaiming of presence, and greater confidence in the face of cancer recurrence. Implications for theory and clinical treatment are discussed.