Systematized Review of Psychotherapeutic Components of Psilocybin-Assisted Psychotherapy

The first stage of PAP included at least one pretreatment session (N=11, 100%). During pretreatment, therapists met with participants to discuss psilocybin’s effects and to build the therapeutic alliance prior to treatment (N=11). The primary intention of these sessions across all 11 trials was to prepare participants to receive psilocybin safely and to help them feel supported while under psilocybin’s effects. This aspect of pretreatment has led some researchers to describe this stage of treatment as the preparatory stage (17). Pretreatment sessions varied among studies in total hours (mean±SD=6.06±1.70) and number of sessions (3.31±1.44). Preparation for psilocybin occurred before the first psilocybin treatment session in all 11 studies, and two studies indicated inclusion of additional preparatory sessions for subsequent treatment sessions (10, 17). With one exception (16), all of the studies involved a discussion of the participant’s life experiences, experiences with the presenting problem, and/or setting intentions or goals for the treatment.

Treatment sessions were the next stage of PAP, during which psilocybin was administered to participants; this was the only stage of psilocybin treatment in which psilocybin was administered (N=11, 100%). Details regarding the dosage of psilocybin or control in each clinical trial are provided in Table 4. Treatment sessions varied both in frequency (mean=2.08±0.76) and length (7.46±0.78 hours), but all 11 studies asked the participant to lie down, wear eyeshades, and listen to a standardized playlist of music for the majority of the session or sessions. Ten studies (91%) administered psilocybin to participants in a decorated room intended to make the participant comfortable; decorations were often designed to resemble a living room (N=8, 73%). The remaining study (15) did not specify the room design. In each study, direct interaction between participants and therapists increased toward the end of the session, typically during the last hour.

Treatment sessions were conducted in a nondirective and supportive setting (N=11). Research suggests that psilocybin administered in a nondirective and supportive setting facilitates spiritually or meaningfully significant experiences (2, 25) and the relaxing of beliefs underlying psychological distress (26). This nondirective supportive model of therapy with psilocybin is analogous to the psychedelic model used as early as the 1950s; the key difference between the mid-20th century model and today’s updated psychedelic model is the implementation of carefully constructed control conditions (1, 2). Therapists are present throughout the session to provide this support. This laissez-faire approach to treatment sessions shares many similarities with MDMA-assisted psychotherapy, which identifies an individual’s inner healing intelligence as the primary mechanism of change in treatment (27). The nondirective approach to therapy takes this model one step further, suggesting that the individual, not the psychedelic nor the therapists, is the source of the healing; PAP only facilitates this process of inner healing (27). Therapy involved in treatment sessions has been referred to as a modified form of Rogerian, existential, and logotherapy modalities (17).

All 11 studies explicitly directed participants to focus their intention on their internal experience or journey. Each of the 11 studies followed the nondirective supportive therapeutic model, which attempts to facilitate a transformative, mystical-type experience (2, 10, 25). The therapists provided psychological support in several forms during the session, such as through physical reassurance and supportive touch (3, 4), reality orientation (4, 17), and interpersonal support with nonjudgmental, empathic listening (3, 4, 17).

At least 10 of the studies, with the possible exception of Moreno et al. (16), included posttreatment sessions pertaining to the experience and resulting effects of the previous psilocybin treatment session. Nine studies reported the number of posttreatment sessions, and seven of the studies also provided the total number of hours devoted to posttreatment sessions. Attempts to contact study authors for missing data relevant to posttreatment sessions were unsuccessful.

The number of posttreatment sessions (mean=6.17±4.61, N=10), as well as the length of these sessions (8.72±5.96, N=7), differed among studies. Ten studies (91%) indicated discussion of the participant’s experiences in at least one posttreatment session; Moreno et al. (16) included this discussion at the end of the treatment session but did not suggest the presence of posttreatment sessions. Discussion of the treatment session was often referred to as the “integration process” of the treatment, leading some studies to label posttreatment sessions as “integration sessions” (4, 16). Posttreatment or integration sessions often occurred between doses (N=8), and four studies (36%) included at least three sessions between administrations of psilocybin.

Music was used during the treatment sessions of all 11 clinical trials. A study (28) on the role of music in psychedelic therapy has stated that the purpose of including music is to support and foster meaningful experiences during the session. This purpose is in accord with early psychedelic research, in which music’s role in psychedelic therapy was to facilitate emotional release and provide direction and structure to the experience (29). The use of music with psilocybin corresponds to the purpose of music therapy, namely, to induce or magnify an emotional state to achieve therapeutic progress (30). Specifically, psilocybin research has relied on the passive or receptive components of music therapy rather than on active or creative components (30).

All 11 studies included a standardized playlist of music during treatment sessions, although two studies allowed some flexibility in the music selection either toward the end of the session (16) or when it seemed appropriate (9). Grob et al. (14) standardized the playlist shortly after the trial began. The content of the playlists varied among studies, but generally included a mix of neoclassical, classical, or ambient music with minimal lyrics (3, 11). Traditionally, music in psychedelic therapy has been tailored to the individual; however, some authors (14) indicated that they decided to standardize the playlist to allow for more accurate comparisons of outcomes between participants.

Bogenschutz et al. (10) incorporated seven sessions of motivational enhancement therapy (MET) into the pretreatment and posttreatment sessions. MET uses motivational interviewing and cognitive-behavioral therapy (CBT) to support individuals’ efforts to reduce or quit drinking, which was the behavior targeted by that particular study (10). The study authors indicated that 12 sessions of psychosocial interventions were included in the study, consisting of seven sessions of MET, three preparation sessions, and two debriefing sessions. The authors further elaborated that these 12 sessions were split into four sessions prior to the first treatment session, four between treatment sessions, and four after the second treatment session. Although the authors did not indicate the placement of psychosocial interventions into these groups of four sessions, the information provided suggests that MET was incorporated before and after treatment sessions.

Johnson et al. (15) used CBT in pretreatment sessions for tobacco cessation with a sample of 15 individuals who smoked an average of 19 cigarettes per day. The study implemented four pretreatment sessions of CBT for tobacco cessation. Components of CBT used in the study included a signed contract to quit, program cards to be read each time a participant smoked a cigarette or had an urge to smoke, a smoking diary, a brief motivational statement, psychoeducation regarding the financial and health consequences of smoking, cognitive reframing, assignment of a target quit date, and support for dealing with urges after the target date. In addition to these CBT components, pretreatment sessions included preparation of individuals for psilocybin treatment and discussion of the participant’s developmental years, interpersonal relationships, work, hobbies, and other relevant information. Material covered in the pretreatment CBT sessions was reviewed during the posttreatment sessions, along with staff provision of support for smoking abstinence and discussion of the session experience.

Anderson et al. (9) modified an existing adaptation of supportive-expressive group therapy (SEGT), a palliative care–focused existential modality of therapy. The authors cited SEGT’s focus on facilitating present-moment processing, emotional expression, and reducing death anxiety (9), which has been described in qualitative reports of psilocybin sessions (20, 21). Modifications to SEGT for this study included the substitution of breathing exercises and guided meditations instead of autohypnosis. These modifications were intended to aid in facilitating group sessions and to provide tools for mindfulness and self-regulation for use in psilocybin sessions.

Ross et al. (4) used CBT in posttreatment sessions for individuals experiencing anxiety and depression in the context of life-threatening cancer. This study used other modalities in addition to CBT, including supportive psychotherapy, existentially oriented psychotherapies, and psychodynamic and/or psychoanalytic therapy. The authors justified incorporating CBT, supportive therapy, and existential therapy by emphasizing the relevance of these therapies for treating anxiety and depression of individuals with advanced-stage cancer (4). Psychodynamic and psychoanalytic therapy, on the other hand, were selected to assist participants in interpreting the experiences of treatment sessions (4). Psychoanalysis was used in psycholytic therapy, a modified form of psychoanalytic therapy incorporating low-to-moderate doses of psychedelics, which was used in early studies of psychedelics (2, 4).

Ross et al. (4) began the integration process of PAP toward the end of the treatment sessions in a format the study authors likened to that of psycholytic therapy. The study authors (4) provided three 2-hour sessions of psychotherapy in the pretreatment stage and after each treatment session, for a total of 12 sessions of psychotherapy. Although the authors did not indicate the specific modalities used in the pretreatment sessions, the stated goals of these preparatory meetings included intention setting, discussion of psychological and existential distress related to the cancer, and the status of the individual’s present relationships. After being contacted for additional information, some study authors revealed that in all stages of psilocybin therapy, they took an eclectic approach to preparing, facilitating, and integrating the psilocybin experiences, borrowing primarily from supportive and existential therapy (11, 14, 17).

Body scanning is a mindfulness technique for developing attentive flexibility by shifting focus through different regions of the body (32). One study (15) had participants engage in a 10-minute body scan at the beginning of each pretreatment session and in open-ended narrative writing at the end of treatment sessions to describe their psilocybin experiences. This narrative writing was discussed with therapists the next day during a 1-hour integration meeting (15). Similarly, another study (13) asked participants to journal about their experiences and struggles with incorporating aspects of the psilocybin treatment into their daily lives.

Guided imagery is a therapeutic technique often associated with psychodynamic therapy, in which individuals lie on a couch with minimal external stimuli as the clinician depicts visual scenery (such as a meadow) to the individual (33). Guided imagery was used in two of the studies (3, 15). Johnson et al. (15) included guided imagery during pretreatment and posttreatment sessions and in the last hour of the first treatment session; the authors of this study did not indicate the intended effects of guided imagery, although Carhart-Harris et al. (3) indicated use of guided imagery to enhance relaxation. Nicholas et al. (17) also offered guided meditation to aid participants in relaxing prior to psilocybin administration.

Integration is loosely defined as reflecting on the unusual thoughts and feelings arising from the psilocybin experience and exploring implications of the experience for the targeted areas of change (1, 2, 24). Eight studies indicated incorporation of integration into posttreatment sessions. Grob et al. (14) and Moreno et al. (16) did not indicate inclusion of any posttreatment sessions, and Carhart-Harris et al. (3) did not specify the content of posttreatment sessions. Attempts to contact the authors of these studies failed. Integration sessions were sometimes referred to as “debriefing sessions” (3, 10) or “support meetings” (1, 15).

Griffiths et al. (13) explored the use of meditation practices with psilocybin, asking participants to engage in sitting meditation and daily awareness practice before and after treatment sessions. After the psilocybin treatment, this study incorporated individual meetings and dialogue-group sessions into the intervention. In these group sessions, participants discussed their psilocybin treatment experiences, although these sessions primarily focused on implementing and sustaining meditation and journaling practices into daily life. The study relied on Easwaran et al.’s (34) book on meditation as the primary teaching resource for the group. No specific therapeutic modality was specified for the group. Nicholas et al. (17) also offered opportunities for meditation before and during the final hour of treatment sessions.

Quantitative outcomes of the clinical trials are displayed in Table 1. Each study used several psychological outcome measures, including the Beck Depression Inventory (35), State-Trait Anxiety Inventory (36), Persisting Effects Questionnaire (25), Timeline Follow-Back (37), and the Yale-Brown Obsessive-Compulsive Scale (38). Table 1 presents results for measures common to each of the studies working with a particular population, regardless of whether these measures were of primary or secondary outcomes. All but one study (14) achieved statistically significant improvements in the targeted outcomes, such as depression and anxiety (3, 4, 11, 12).

Johnson et al. (15) demonstrated 7-day point prevalence of abstinence from smoking among 80% of participants at the 6-month follow-up. A 12-month follow-up of this trial indicated that 53% of participants had maintained abstinence since the target quit date (39). Nicholas et al. (17) demonstrated moderate effect sizes for increased positive attitudes and mood in their study of healthy participants. Seven studies (3, 4, 9–13) reported large effect sizes for the therapeutically relevant constructs (Table 1). Four of the five studies measuring depression and anxiety demonstrated clinically significant reductions in these conditions (3, 4, 11, 12). Grob et al. (14) eventually reached significance at the 6-month follow-up. These outcomes suggest that psilocybin may be an effective treatment for a range of psychological disturbances.

Qualitative data can capture valuable information missed by quantitative analysis, especially in the field of psychopathology (40). Noorani et al. (19) identified pretreatment sessions and the therapeutic relationship as two essential components of successful treatment. Watts et al. (21) used thematic analysis with participants from Carhart-Harris et al.’s study (3); through conversations with participants, they identified two fundamental change processes underlying PAP. One of these changes was a shift from feeling disconnected to feeling connected with oneself, others, and the world (21). The second change was a process of shifting from avoidance of emotions to acceptance of emotions during and after PAP. Participants from another study (15) stated that they gained insight into themselves and their reasons for smoking. These examples revealed a common thread between these four studies: in PAP, participants seem to gain novel insights into themselves, their presenting problems, or their relationship with those problems. A participant from another study (18) indicated that she began practicing meditation after PAP in order to return to a state of mind she referred to as a “really wonderful emptiness—that kind of really good feeling of nothingness” (20).

Griffiths et al. (13) published the only study in this review that measured the effects of psychotherapy in the analysis. This study included psychotherapy as an independent variable to ascertain the effects of psychotherapy on outcomes in PAP. Although the study did not indicate use of a specific psychotherapeutic modality, the authors reported the use of meditation practices, journaling, spiritual practices, and group discussion of the psilocybin experience. The results of this study suggested that individuals with greater psychotherapeutic support throughout treatment exhibited greater short- and long-term effects in domains such as daily life experiences, gratitude, and meaning or purpose in life (13). No other study in this review accounted for the effects of psychotherapy interventions on participant outcomes, except for the effect of music in treatment sessions (21–23). Qualitative studies (20–22) revealed that music was identified by participants as an important component of the experience. A follow-up study (22) of Ross and colleagues’ clinical trial revealed that all 13 participants described the music played during the session as having a central role in their experiencing of the treatment. In fact, participants described the music as a conduit to the experience (22) and a guide through challenging emotions (23). Watts et al.’s (21) qualitative study of individuals who received psilocybin for treatment-resistant depression revealed that music enabled participants to experience and accept painful emotions. Together, these data suggest that music therapy may be integral in producing the clinically significant outcomes seen in PAP studies.