Can psychedelics enhance group psychotherapy? A discussion on the therapeutic factors

Group psychotherapy

Group psychotherapy is defined by Irvin Yalom (2005) as a social therapy which gives its members the chance to interact with others who can relate to their experiences. It is thought to ‘generate a positive, self-reinforcing loop: trust–self-disclosure–empathy–acceptance–trust’ (Yalom, 2005).

Today, group psychotherapy provides a solution to the problem of increasing psychotherapy demand by treating multiple individuals simultaneously, thereby reducing wait list delays and increasing accessibility and cost efficiency (Malhotra and Baker, 2022). While the group psychotherapy method is in itself very diverse in relation to diagnoses and ways of conduct, it is found to be particularly useful for homogeneous groups of patients with similar conditions, therapeutic goals and therapy stages (Burlingame et al., 2003; Malcolm et al., 2016; Wolgensinger, 2015). Research has demonstrated that group psychotherapy is an effective method for treating a variety of psychiatric and behavioural disorders, and experimental studies comparing individual therapy and group therapy indicate that group therapy is about as effective as individual therapy, although the great diversity of approaches leads to heterogeneous results (Burlingame et al., 2016; Cuijpers et al., 2008; Friedman, 2013).

Psychedelic substances

‘Psychedelic’ (or ‘mind-revealing’) substances are a class of psychoactive drugs which produce temporary and often dramatic changes in perception, thought and emotion (Nichols, 2016). Psychedelics are ingested at various doses, ranging from sub-perceptual ‘microdoses’ to doses which produce strong altered states of consciousness. Microdoses have not yet consistently shown significant effects on well-being or in therapy (Polito and Liknaitzky, 2022; Seragnoli et al., 2021), but higher doses have been associated with lasting positive changes in psychopathology and well-being (Gasser et al., 2015; Noorani et al., 2018). Classic psychedelics, such as lysergic acid diethylamide (LSD) and psilocin, share agonist action at the 5-hydroxytryptamine 2A (5-HT2A) receptor (De Gregorio et al., 2021). Two other groups of non-classical psychedelics include dissociative anaesthetics such as ketamine and entactogens such as 3,4-methylenodioxymetamphetamine (MDMA), the latter of which produces psychedelic-like effects, predominantly an affective state of enhanced mood, profound well-being, happiness, and increased extroversion and sociability (Vollenweider, 2001). Due to its pro-social effects, MDMA may be particularly suitable for group therapy. MDMA increases synaptic levels of the monoamine neurotransmitters serotonin, dopamine and norepinephrine and blocks their reuptake, which is thought to be the primary source of its specific psychological effect (Montgomery and Roberts, 2022).

Psychedelics are considered safe for clinical use. Classic psychedelics have a very favourable safety profile, showing low physiological toxicity and potential for dependency (Gable, 2004; Hasler et al., 2004; Johnson et al., 2008; Nutt et al., 2010). Both classic psychedelics and MDMA can dose dependently increase heart rate, blood pressure and body temperature (Holze et al., 2022a; Vizeli and Liechti, 2017). They can also cause acute psychological distress, which is usually manageable with interpersonal support (Johnson et al., 2008). Serious adverse events are rare in both healthy and clinical populations (Breeksema et al., 2022), suggesting that well-trained therapists would likely be able to manage adverse effects from psychedelics in a group setting.

Set and setting

Psychedelics interact both with the mindset of the patients, otherwise known as set, and the external conditions, otherwise known as setting (Reiff et al., 2020). Like IPAP, PAGP requires a preparatory phase to optimize these factors before administering any psychedelics. Set refers to beliefs, attitudes, choices and motivations, and therapists must help their patients adopt a suitable mindset before working with psychedelics (Schenberg, 2018; Winkelman, 2021). In our experience, working on the set in a group setting means not only that each individual establishes an intention towards introspection, but also a strong focus on the group’s intentions and processes. Conjointly, the setting should be organized during the preparatory phase of therapy and refers to the group’s atmosphere and environment, as well as the definition of the therapist role (Schenberg, 2018; Winkelman, 2021). Setting also includes the social context and any instructions given by the therapist, as well as the physical environment and the choice of music. Music is nearly ubiquitous in psychedelic therapy, even if the field still lack studies on it as a specific factor, and it can provide emotional guidance and synchronicity within the group (Winkelman, 2021). A safe and inviting atmosphere has also been shown to reduce acute psychological distress (Johnson et al., 2008) and may also help participants feel safe within the often intense and chaotic nature of sensory and emotional experiences in psychedelic sessions (Carhart-Harris et al., 2018). In addition, the presence of other group participants can increase physiological responses to psychedelics (i.e. heart rate), as well as make the subjective drug effects more intense (Bershad et al., 2016; Kirkpatrick et al., 2015).

One essential difference between conventional group therapy and PAGP may be that PAGP accelerates the therapeutic process of individuals within the group dynamic, without reducing the amount of emotional experiences (Blewett, 1971). It does so by adding emotionally intense, autobiographical and insightful psychedelic experiences into the course of therapy, which are experienced and discussed together. Thus, PAGP holds the potential to not only provide a socially supportive framework for therapy, but also to shorten recovery time, potentially reducing both human suffering and polypharmacy and drug dependency problems (Brown et al., 2005).

Individual versus group psychedelic therapy

PAGP falls into the category of applied psychedelic research, and it differs from current individual approaches (see Figure 1). Psychedelic therapy, as it is currently used in clinical trials, involves one to several high-dose sessions which are meant to produce intense and profound psychedelic experiences (Schenberg, 2018). These may contain personal insights, belief changes, emotional releases and transcendental ‘mystical’ experiences which are viewed as therapeutically beneficial (van Elk and Yaden, 2022). Psychotherapeutic integration sessions are sometimes kept to the minimum required for ensuring safety, though some researchers and clinicians have observed that psychedelic substance intake without active therapeutic accompaniment is insufficient for clinical improvement (Read and Papaspyrou, 2021). Patients often feel that their experiences with psychedelic substances are difficult to describe to those without first-hand knowledge, and if they have no one to relate to, they may withdraw socially. Such reactions are not uncommon even in healthy trial participants, and they have led to the emergence of non-professional psychedelic integration groups for past research participants (Noorani, 2019). Clearly, there is a need for more professionally accompanied interpersonal support, and group psychotherapy would be uniquely able to provide it.

IPAP sometimes addresses this problem by combining individual psychotherapy with a few introspection-focused sessions with medium- to high-dose psychedelics (Richards, 2016), often several months apart. Such interventions have been found to be successful treatments for various psychiatric disorders (Luoma et al., 2020), including treatment-resistant depression (Romeo et al., 2020), anxiety disorders (Dos Santos et al., 2021; Holze et al., 2022b), illness-related psychological distress (Gasser et al., 2015; Griffiths et al., 2016), substance use disorders (Berlowitz et al., 2019; Bogenschutz et al., 2022; Johnson et al., 2014) and PTSD (Jerome et al., 2020; Mitchell et al., 2021). IPAP entails preparatory and integrative sessions and is especially useful when the patient needs a high level of support from the clinician, for example, when working with complex disorders or a severe fear of closeness and intimacy (Oehen, 2021). However, high-dose sessions can last for many hours and are not only straining for the therapist(s), but also very costly (Beaussant et al., 2021; Teixeira et al., 2022; Vargas et al., 2021). Therefore, accommodating the IPAP model on a large scale would seem to require reconfiguring healthcare organization (Greenway et al., 2020). Medical historians have pointed out that in the mid-20th century, the laboriousness and costs of IPAP were disproportionally large compared to other treatments (Richert and Dyck, 2020).

Another existing model is ‘psycholytic therapy’, which was extensively researched in Europe in the mid- to late 20th century, with over 300 studies published on this topic (Passie, 1997). Later, it was adopted by the Swiss Medical Society for Psycholytic Therapy (SÄPT) and is still being practiced. Psycholytic therapy includes several sessions with different psychedelics, often in groups and with a varying dose range (e.g. MDMA in the first session, followed by a more intense session with LSD or a combination of both) (Passie, 1997; Reiff et al., 2020). This approach takes advantage of the different modes of substance action in combination with evolving therapeutic processes, environments and a greater access to the unconscious while discharging psychic tension (Reiff et al., 2020). The focus of this therapeutic approach is on remembering and understanding personal life experiences as well as uncovering the inner functioning of one’s mind. Preparation and integration at different intensity levels involves more personal, psychodynamic and depth psychology concepts (Jungaberle and Verres, 2008), rather than the US-American humanistic, transcendental characteristics used in IPAP, which primarily seeks to generate overwhelming peak experiences (Reiff et al., 2020). While IPAP and PAGP approaches can both be therapeutic, they require different forms of behaviour from the therapist and patients. In our experience, PAGP tends to bring the therapists into a more peripheral role with shared tasks and responsibilities, because mutual support and feedback often come from other group members.

Furthermore, in our experience with PAGP, we see a reduction in therapy costs for each patient because therapists can split the costs among all participants of the group. These costs include the therapists’ work time, use of the therapeutic space, and, from the patients’ perspective, the cost of transportation. The group setting is also both more rewarding and more cost-efficient than individual sessions for most problems treated with psychedelic therapy (Oehen, 2013).

Contraindications

Specific contraindications for PAGP need more investigation and have thus far differed between PAGP studies. General exclusion criteria for any psychedelic treatment currently include pregnancy or breastfeeding, cardiovascular diseases, certain medications, and a history of schizophrenia or other psychotic disorders; these are further specified elsewhere (Johnson et al., 2008). PAGP-specific contraindications mentioned in the literature include borderline personality disorder (Anderson et al., 2020; Oehen and Gasser, 2022), bipolar disorder in patients and in first-degree relatives, acute drug dependency (Oehen and Gasser, 2022) and severe lack of social skills (Gasser, 2022). In the long-term practice of PAGP in Switzerland, no other specific contraindications to PAGP have been documented. Though PAGP in Switzerland still occurs on a relatively small scale, it appears to be safe when following the abovementioned guidelines.

Instillation of hope

The installation of hope unfolds in two directions. First, it is the patient’s belief in their own capability for overcoming their illness. Second, it is belief in the effect of the therapy itself. Both are required for the patient to stay in therapy, and they are therefore the most crucial factors (Yalom, 2005).

Sometimes, the increased affectivity and insights derived from psychedelic sessions can bolster patients’ belief that recovery is possible. Increased belief in one’s power to recover has been seen in patients’ experiences with psilocybin and MDMA in multiple studies (Breeksema et al., 2020; Noorani et al., 2018; Watts et al., 2017). Psychedelics can also enhance autobiographical memory recollection (Baggott et al., 2016), through which patients may realize the depth, complexity and nuances of his or her personal life story. This may help patients to broaden their autobiographical perspective, bolstering both hope and motivation for recovery. In qualitative interviews conducted by Passie (2012), PAGP patients have described revisiting experiences, people and events from their past, together with an emerging sense of deep primal trust in their own capabilities and in the world at large. These realizations have been particularly associated with challenging experiences, adding a sense of curiosity in painful moments, as if patients anticipate the coming relief.

In addition, PAGP patients benefit from witnessing and empathizing with the success of other group members, which may be augmented by psychedelics’ capacity to enhance emotional empathy (Dolder et al., 2016; Pokorny et al., 2017; Schmid et al., 2014). The success of others can inspire patients to envision following a similar path and realize their own self-efficacy, similar to the effects witnessed in other group therapies (Johnson and Sullivan-Marx, 2006).

Universality

The concept of universality addresses the patient’s feeling ‘that they are unique in their wretchedness’ (Yalom, 2005). As group members begin to disclose these concerns, they create the opportunity to relate to each other. Yalom (2005) describes this process as a ‘welcome to the human race’ experience. Its ultimate stage is the realization that there is no human deed or thought that is foreign to others.

Without the feeling of universality, there is often an increased focus on one’s own mental state, greater negative self-attribution and rumination, and reduced attention to others. This can result in social isolation and difficulties in interpersonal relationships. In sharing their experiences within a structured group environment, however, patients start to understand that others share similar thoughts, feelings and problems. As the PAGP therapist Raquel Bennett observes,

In individual treatment, people often felt very alone, that they were the only person on earth dealing with whatever problem they were living with. In the group, people quickly found that there were other people who had similar issues and challenges (Lawlor, 2021).

A recent qualitative analysis of PAGP reports a reduction in this habitual self-focus, leading to a sense of belonging and interdependence in the majority of patients (Agin-Liebes et al., 2021). This suggests that treatment with psychedelics in a group setting can help to develop the feeling of universality.

Though group therapy alone can reduce feelings of uniqueness, psychedelics may amplify this effect. Psilocybin has been shown to catalyse experiences of unity, in which people feel like they are one with other people or their surroundings (Preller et al., 2016). Psychedelics are also known for their ability to temporarily eliminate the subjective feeling of having a self, sometimes referred to as ego dissolution, which people often describe as the feeling of becoming ‘one’ with other people or the environment (Nour et al., 2016). Psychedelics may cause ego dissolution by altering the functional connectivity of the default mode network (DMN), which is implicated in self-referential processing (Carhart-Harris et al., 2016; Mason et al., 2020; Palhano-Fontes et al., 2015; Tagliazucchi et al., 2016). Without the self, there can be no exaggerated focus on one’s individual mental state. This may be particularly therapeutic in patients suffering from depression, for which perceived uniqueness of one’s suffering is a prominent feature. Depression is also hypothesized to correlate with an overly active DMN and executive network (Vollenweider and Smallridge, 2022).

Group therapy alone can increase feelings of universality, and psychedelic-induced changes in beliefs about the nature of reality can do the same. Put together, we theorize that they complement each other: Interactions with other group members offer insight into the problems they have in common, and psychedelics allow patients to temporarily step outside of themselves, both of which work to reduce focus on one’s own individual suffering.

Imparting information

During group therapy, both the therapists and other patients may share information about mental health, mental illness and general psychological dynamics, as well as advice, suggestions or direct guidance (Yalom, 2005). These processes constitute the therapeutic factor of imparting information.

Group therapy with psychedelic substances includes an additional source of information, apart from therapists and other patients: the personal insights derived from psychedelic experiences themselves. Patients often describe these in terms of learning experiences, and they can feel like they have acquired important information about themselves, their mental habits and their capabilities (Breeksema et al., 2020; Wolff et al., 2020). As participants undergo these experiences, the psychedelic therapist can support, orient and deepen the process. This is crucial because learning experiences on psychedelics are sometimes painful; psychedelics tend to intensify therapeutic processes, occasionally leading to challenging experiences for the patient (Carbonaro et al., 2016; Roseman et al., 2018b). In group therapy, all learning experiences can be processed and shared within the group, including challenging ones, and participants can be supported by both the therapists and their peers. Because PAGP encompasses both expression-oriented phases and introspection-oriented phases within the psychedelic session (Jungaberle and Verres, 2008), patients can benefit from both.

Altruism

According to Yalom (2005), the members of a therapy group profit not only from receiving help, but also from the intrinsic motivation to give something back. Giving tends to remedy the feeling of ‘being a burden’ and it can bring back a sense of useful contribution, value and meaning in life. The opportunity for reciprocal interactions offers a unique process to patients in group therapy, which they often use and benefit from.

Psychedelics tend to enhance prosocial feelings and behaviour. In particular, MDMA has increased self-reported feelings of sociability across multiple placebo-controlled trials, with moderate to large effects on extraversion, friendliness and trust (Regan et al., 2021; Schmid et al., 2014). MDMA may also increase emotional empathy and prosocial behaviour (Hysek et al., 2014), though some environments may not be conducive to these effects (Borissova et al., 2021). LSD and psilocybin are also known to increase emotional empathy and sociality (Dolder et al., 2016; Pokorny et al., 2017; Schmid et al., 2014), and psychedelics may make it easier to see things from another’s perspective (Thal et al., 2021).

Studies also indicate that reciprocity and altruistic behaviour are more prominent when the other person is a friend, and not a stranger (Kirkpatrick et al., 2015; Kuypers et al., 2014). In PAGP, participants have the opportunity to become familiar with each other during multiple therapy sessions and often form friendships even outside of the therapy group. In addition, Preller and Vollenweider (2019) stated that after psychedelic interventions altruistic behaviour occurs predominantly in participants with low altruism at baseline, which may be of particular interest in clinical populations, as altruism and other prosocial behaviour resulting after psychedelic therapy have been documented as long-term outcomes in a clinical addiction study (Noorani et al., 2018).

With MDMA, these effects may partly depend on action at the serotonin transporter within the nucleus accumbens (Curry et al., 2019; Heifets et al., 2019; Kamilar-Britt and Bedi, 2015; Mukai et al., 2020). In addition, both MDMA and classic psychedelics increase oxytocin levels (Holze et al., 2019, 2022c; Nardou et al., 2019). Oxytocin likely facilitates many prosocial behaviours, including altruism, cooperation, caring for others and trust (Marsh et al., 2021).

From these results, we hypothesize that in PAGP, psychedelics promote altruism in patients’ interactions with each other. Patients may experience more feelings of empathy, as well as perspective shifts and other prosocial impulses, which they can directly put into practice in the group setting with people they have come to know relatively well.

The corrective recapitulation of the primary family group

Yalom (2005) describes the resemblance of the therapy group to a family structure, often triggering implicit memories of negative experiences in the primary family of the patient. This causes discomfort at first, but once overcome, interacting with other group members in the mimicry of their primary family patterns leads to therapeutically important realizations. While this may also happen in individual therapy, the group dynamic tends to enhance this effect, revealing initial behavioural patterns and allowing them to be re-lived in a corrective manner.

An emotionally positive psychedelic group experience, in which participants are open, caring and emotionally close to each other, has the potential to be a corrective learning experience. The group can serve as a model for a loving and supportive primary family group. This is especially beneficial for victims of childhood neglect and violence who have few memories and imprints of a positive familial atmosphere. In addition, because psychedelics improve autobiographical memory (Carhart-Harris et al., 2012; Garcia-Romeu and Richards, 2018; Healy, 2021), patients may have freer access to relevant memories concerning family relationships. Throughout PAGP, patients can develop a new standard for a healthy family structure, discovering that they are able to express and receive love and kindness both during therapy and afterwards.

From experience, Oehen and Gasser (2022) observe that ‘preconscious conflicts and ineffable childhood dramas tended to be re-enacted in the group’ and that such effects, though possible within any group therapy, can be enhanced by PAGP. They go on to describe a case study:

[. . .] after being in intensive psychotherapy for more than 1 year she had her first MDMA experience in a group setting. She labelled it an ‘emotional breakthrough’ and [experienced] positive and negative emotions of previously unknown intensity [. . .]. In the group, she befriended a fellow patient and developed a sister-transference to her. The processing of this transference reaction was very important to overcome her chronic feelings of guilt toward her biological sister and to gain independence, self-worth, and authenticity. This led to her being able to interact with her fellow patient (and the others) in a good and increasingly mature way, with clear boundaries.

However, problematic group dynamics, which reinforce dysfunctional behavioural patterns, can also occur within group psychotherapy and have also been observed in the Swiss limited medical use program of PAGP. Such dynamics could sometimes last for several sessions until they were appropriately addressed and dealt with by the therapists. Nevertheless, such problems have not thus far led to an overall negative outcome or a reinforcement of dysfunctional patterns in individual participants.

From today’s perspective, this therapeutic factor can be extended towards not only the primary family group and the individuals’ unconscious inner systems of tension or COEX systems (systems of condensed experience) (Grof, 2000), but also to any other autobiographical memories of relational nature. This could be part of the general phenomenon that psychedelics disrupt psychological habits, fixed cognitions and other constraints or ‘priors’ which limit one’s thinking (Carhart-Harris and Friston, 2019; Swanson, 2018). Patients may gain an increased awareness of avoidance tendencies in difficult social situations (Gasser et al., 2015), potentially allowing them to process frightening stimuli in a relatively unconstrained mind (Frecska, 2011), yet still within the supportive framework provided by other group members and therapists. This could allow for a more open and positive conversation about traumatic memories in the integration sessions.

Development of socializing techniques

The development of basic social skills is a crucial therapeutic factor present in group therapy, although it varies greatly depending on group goals. To promote this, therapists can use both direct techniques (e.g. role-play) and indirect, dynamic techniques (e.g. interpersonal feedback) (Yalom, 2005).

In addition to the effects on pro-social behaviour discussed above, psychedelics may also benefit the development of social behaviour via changes in mood (Preller and Vollenweider, 2019). Psychedelics tend to enhance positive mood, as well as reduce the response to negative facial expressions and increase goal-directed behaviour towards positive compared to negative cues (Kometer et al., 2012; Preller and Vollenweider, 2019; Rocha et al., 2019; Roseman et al., 2018a; Wardle and de Wit, 2014). MDMA also enhances ratings of pleasantness for affective touch (Bershad et al., 2019) and significantly increases the emotional and social content of spontaneous speech, emotional disclosure and comfort with describing emotional memories (Baggott et al., 2016; Bershad et al., 2016). Such findings are hypothesized to lead to an increased social interest (Bedi et al., 2010), more acceptance of group interactions and increased responsiveness to therapeutic interventions from the clinician. These pro-social effects outlast the acute drug effects (Noorani et al., 2018), meaning that socializing techniques may be of benefit in the integration sessions.

Psychedelic intake may also make patients less sensitive to social exclusion. After exposure to MDMA or psilocybin, participants in one study showed reduced feelings of social exclusion in the CyberBall task, as well as a significant reduction in activation of the right anterior mid-cingulate cortex, a key region for social exclusion processing (Frye et al., 2014; Preller et al., 2016). Psychedelics may therefore reduce social pain processing, which is associated with changes in self-experience. During therapy, patients may therefore take social pain less personally, which may provide an opportunity to reflect more mindfully on social behaviour. Adding to this, MDMA interventions have been reported to reduce interpersonal defensiveness (Bedi et al., 2009; Mithoefer et al., 2011; Oehen et al., 2013), which may help patients to break out of the blaming communication style and begin to open up and reconnect to others.

Imitative behaviour

During group therapy, patients have the tendency to imitate not only the behaviour of the therapist, but also that of other group members when learning how to address problems (Yalom, 2005). This therapeutic effect generally plays a more prominent role in the beginning of therapy and lessens after a while, as patients determine the usefulness of the mimicked behaviours and decide whether to adapt them long-term or not.

Imitative behaviour in PAGP has often been described, but its effects are not yet entirely understood. Eric Osborne, the founder of a psychedelic retreat centre, states

Within the direct experience, how many times we have seen the release of someone in the group, possibly even at a distance, that has impact on others within the group and feeling OK to just let it go. [. . .] We have instances where someone’s outburst or emotional release will trigger someone else’s. (Osborne and Townsend, 2020)

Because psychedelics can increase empathy (Holze et al., 2021; Mason et al., 2019), group members may become more aware of the distress of others in the group. If they then mimic the perceived behaviour, they may find themselves seeking an explanation for it within their own functioning. This may, in turn, help them in the process of identifying their own disturbing emotions and follows a corrective adjustment in the gradually evolving environment of the PAGP setting (Blewett, 1971).

Passie and Dürst (2008) analysed interviews of patients after PAGP and summarized multiple examples of members going into the social ‘roles’ of other members during the psychedelic interventions. Through this imitative behaviour, they were said to be exploring other gender, family or work roles, thereby empathizing even with members that seemed to have completely different situations from themselves (Passie, 2012). In summary, imitative behaviour has been documented in relation to PAGP, though more research is needed to analyse this phenomenon and its usefulness in more detail.

Interpersonal learning

Yalom (2005) explains this complex therapeutic factor by dividing it into three main concepts. First, all members must understand the importance of interpersonal relationships for health and well-being. Second, patients should have corrective emotional experiences which disconfirm the pathogenic beliefs arising from negative memories of previous social interactions. Lastly, interpersonal learning experiences will develop into a social microcosm over time, in which group members will continuously become more comfortable with expressing themselves. As this occurs, they will begin to reveal more maladaptive interpersonal behaviour, which can then be addressed accordingly.

During PAGP, psychedelics may augment corrective emotional experiences. A recent clinical study of PAGP in patients with moderate-to-severe demoralization observed a significant reduction in attachment anxiety 3 months after psychedelic intervention (Stauffer et al., 2021). Other PAGP patients also reported overcoming previous emotional boundaries, resulting in new-found feelings of connectedness with other group members and loved ones during and after the psychedelic intervention. During the treatment and integrative therapy, nearly all participants recognized destructive unconscious habits and previously ineffective coping strategies. In semi-structured interviews, they described an augmented capacity to recognize these past patterns, and this awareness made them feel acceptance, forgiveness and relief. They also acquired a more flexible, multidimensional understanding of themselves and new self-narratives, which aided them in their interactions with other group members, as well as with loved ones (Agin-Liebes et al., 2021).

Another study on PAGP also mentions the therapeutic potential of interpersonal learning, whereby processing shame (e.g. from being a victim of sexual abuse) in the group setting seemed more difficult for some participants. Validation from other members was reportedly helpful, and it both reduced the feeling of having a unique struggle and promoted learning experiences (Anderson et al., 2020). Similarly, interpersonal support can be a powerful amplifier of therapeutic results during PAGP, positively affecting attachment security (Stauffer et al., 2021) and giving instant opportunities to act on newly acquired insights, thereby deepening the learning process (Passie and Dürst, 2008). Gasser (2022) found that PAGP can improve patients’ psychedelic experiences, particularly during difficult moments in their sessions. These difficult moments may include the emergence of negative memories, strong emotions or changes in beliefs. PAGP provides a supportive community that can help individuals navigate these personal challenges and may also highlight commonalities in their unconscious conflicts and relationship dynamics. In this way, group members may experience both a network of supportive relationships and become a role model themselves (Gasser, 2022).

Furthermore, psychedelics may amplify learning processes in general through their effects on neuroplasticity. Neuroplasticity denotes the brain’s ability to modify its connections in an adaptive manner, and it underlies learning of all kinds (Sasmita et al., 2018). Classic psychedelics, MDMA and ketamine have all been shown to lastingly enhance the growth of dendrites and synapses in the neocortex, including in areas relevant for emotional regulation (Calder and Hasler, 2022; Ly et al., 2018). Though research on learning is still sparse, there is some indication that psychedelic intake benefits certain types of learning, including reversal learning and reward learning (Buchborn et al., 2014; Gimpl et al., 1979; Kanen et al., 2022; King et al., 1974; Romano et al., 2010). Group learning processes occurring in PAGP could potentially be amplified by these physiological effects.

Group cohesiveness

Yalom (2005) defines cohesiveness as the group therapy analogue to the therapeutic relationship in individual therapy, although it is more complex because more people are involved. A strong and positive bond, as well as the ability to constructively deal with conflict within the group, is important in altering cognitive distortions and loosening maladaptive beliefs. Group cohesiveness is seen as a precondition for the other factors to function optimally.

Cohesion develops as patients increasingly participate in the group. They begin to influence each other and allow themselves to be influenced, they listen to and accept others, they self-disclose and learn to feel secure, and they protect group norms and resist disruptions. PAGP is a long-term project, because these things take time to develop. Oehen and Gasser (2022) describe how this process might look:

Over time a core group of participants who continuously attended psychedelic-assisted sessions was formed. They also began to meet and provide mutual support outside of the therapy, and new friendships developed. The more advanced they were in their individual long-term therapeutic process the more they engaged directly in supporting and confronting their peers during the sessions in a co-therapeutic sense, as well as taking care of and serving as a model for newcomers, helping to experience what secure attachment, mutual responsibility and care for each other really mean.

This holds imperative value during PAGP, as group sessions with psychedelic substances can improve trust (Schmid et al., 2014) and the ability to connect in a social context, potentially leading to long-lasting and healthy relationships (Kettner et al., 2021; Roseman et al., 2021). MDMA in particular has been found to act as a social catalyst in group settings, amplifying facets of group connectedness (Regan et al., 2021). Blewett (1971) points out that during PAGP, interpersonal connection seems to be relatively free of distortions and empathic bonding occurs with more direct, clear communication. A frequent cause of criticism and conflict within the PAGP group is when participants start communicating inauthentically and hiding feelings during the group exchange, in which case it is often the more experienced members that begin the confrontation spontaneously to re-establish cohesiveness. It is advisable for the conflict to be declared before the psychedelic session so that the resolution can come during the sharing phase, when participants are usually more open and compassionate with each other (Oehen and Gasser, 2022).

The PAGP study by Agin-Liebes et al. (2021) also concludes that after the psychedelic intervention, group members express more feelings of openness and relaxation while being in the group, even if this had not been so just before the session. Other effects included enhanced emotional safety and more willingness to process painful emotions in the group. In addition, patients may feel closer to each other simply by virtue of having shared a psychedelic session: people often find psychedelic effects hard to describe to others who have not experienced them, and the other PAGP group members therefore have a relatively unique capacity to understand each other’s experiences (Nielson et al., 2018; Pedersen et al., 2021).

Connectedness to other members seems to come quickly for some participants, and peer support is described to be especially helpful for tolerating and understanding the content and insights derived from psychedelic experiences (Anderson et al., 2020). Gasser (2022) also elaborates on the fact that when PAGP patients start meeting outside of group sessions, it is welcomed as part of the integration process, as meeting members in ordinary life may help normalize the extraordinary experiences of the psychedelic intervention. Some patients were also relieved to realize that during the vulnerable psychedelic sessions, boundaries were still being respected and thus personal freedom was ensured, which aided the process of opening up to the group on one’s own terms (Passie and Dürst, 2008).

Summarizing the group cohesiveness effects, among others discussed above, is a PAGP patients’ testimony:

I was a very lonely and disconnected person before I joined the group. The psychedelic group experiences helped me to open up, to be close to others, to express myself, to become authentic and to build relationships. I realized that other people also had severe problems and to listen to them and watch them change from one session to the next was fascinating, enlightening and encouraging. To talk to the group about all the bad and painful things that had happened to me as a child was an extremely helpful and healing experience. I appreciated the group rules and the clear structure of the workshops. The preparation evening before and the sharing and integration the morning after the experience were very important parts of the treatment. (Oehen and Gasser, 2022)

Catharsis

Catharsis means intense emotional discharge, and whether negative and positive, it plays an important role in the group therapeutic process. According to Yalom (2005), catharsis alone does not relate to positive outcomes; group psychotherapy following a cathartic experience is essential. It is also intricately related to cohesiveness: ‘members who express strong feelings toward one another and work honestly with these feelings will develop close mutual bonds’ (Yalom, 2005).

As psychedelic intake intensifies affectivity and embodiment (Preller and Vollenweider, 2018), it may lead to cathartic expression in clinical settings (Gasser et al., 2015). During IPAP, emotional release is associated with peak experiences and ego dissolution (Thal et al., 2021) and studies demonstrate these to be a key mediator of successive psychological changes (Bogenschutz et al., 2018; Roseman et al., 2019). Herein lies a strange paradox: though the emotions which arise under the influence of psychedelics may seem stronger than ever before, psychedelic intake also allows patients to withstand previously unbearable emotions. This has been called the ‘helioscope effect’ (Hasler, 2022): Just as a helioscope allows people to directly observe the sun, psychedelics allow patients to access and process deep traumatic memories and overwhelming emotions which were previously too painful to bear.

Recent comparative research has analysed differences between acute drug effects between PAGP and IPAP settings using data from the Swiss limited medical use program (2014–2018). Results show no significant differences (Schmid et al., 2021) indicating that cathartic effects are comparable between the two approaches to psychedelic therapy in Switzerland. To give space to and encourage cathartic processes, Gasser (2022) advises that during PAGP, the first 5 h of the acute substance effect should include little to no interaction with other group members. As the acute drug effects fade, social interactions are encouraged so that patients can process their cathartic experiences together.

There is a possibility that the expectation of great catharsis during psychedelic sessions will lead patients to fear losing control or reliving traumatic memories in front of others. We therefore advise offering the patients a sense of autonomy and control in this process and letting each person discover their boundaries within their personal experience in the psychedelic session. This can be achieved using lower to medium–high doses of psychedelics, which lowers the risk of being overwhelmed. PAGP therapists should also refrain from pushing or forcing patients into processes for which the patient is not ready.

Research shows that as the therapy progresses, members gain more control and can guide themselves more directly towards their questions and problems, as instructed by the therapist (Passie and Dürst, 2008). In our experience, it is ideal for the therapeutic process that participants have enough control to voluntarily surrender themselves to the experience, as unwillingly losing control can lead to the so-called ‘bad trips’. Maintaining some level of control seems to be as important in PAGP as the profound cathartic effect.

Existential factors

In the process of group psychotherapy, Yalom (2005) emphasizes that members learn about the following five existential factors:

1. Recognizing that life is at times unfair and unjust.

2. Recognizing that ultimately there is no escape from life’s pain or from death.

3. Recognizing that no matter how close one gets to other people, one must still face life alone.

4. Facing the basic issues of one’s life, thus living life more honestly and being less caught up in trivialities.

5. Learning to take ultimate responsibility for the way one lives life no matter how much guidance and support one gets from others.

Many current healthcare providers see great potential in psychedelic therapy to treat existential distress (Niles et al., 2021). Clinical research suggests that IPAP can help patients with life-threatening diseases by reducing anxiety, depression, hopelessness and demoralization rapidly, substantially and lastingly (Agin-Liebes et al., 2020; Ross et al., 2016; Schimmel et al., 2022). It may also enhance the sense of meaning in life (Hartogsohn, 2018; Preller et al., 2017).

In PAGP specifically, existential factors were often expressed in a qualitative analysis of demoralized AIDS patients. Psilocybin helped the group members go from ‘trauma oriented’ to ‘growth oriented’ and improve emotional processing and regulation, leading to self-compassion and an empowering internal sense of security (Agin-Liebes et al., 2021). Ayahuasca-assisted therapy in a group retreat helped participants with substance use disorders to not only reduce their use of cocaine and alcohol long term, but also improve their sense of hopefulness, empowerment and meaning in life (Thomas et al., 2013). Contemporary existential psychologists explain these therapeutic effects of psychedelics with their ability to reduce death anxiety by forcing confrontation with mortality, reducing self-focus, shifting metaphysical beliefs, and increasing the feeling of connectedness and the meaningfulness of life (Moreton et al., 2020).

However, existential realizations should not only be attributed to the substance itself. Scharfetter (2008) addresses this issue, expressing concern about clinicians who create unrealistic expectations of psychedelic therapy. Not all suffering should become the object of therapeutic ‘elimination’, as that would be based on the hedonistic illusion of a life free of suffering. Instead, the normality of suffering should be subject to the therapeutic process. Suffering-free spiritual bliss is a gift sometimes given within a psychedelic session, but it cannot be the ultimate life goal. It is the strength and courage, the development of humility and acceptance, that make the pain and grief of one’s own life bearable. Having psychedelic sessions in a group context may thus help to ground people in the realization of personal responsibility by having the continuous support of multiple discussion partners, including the therapists, rather than one saviour in the form of a substance or an idealized, overpowering psychedelic therapist who promises healing and redemption.

Institutional challenges

In the emerging field of clinical treatment and research into psychedelic therapy, the individual approach is currently preferred to PAGP. One can hypothesize many reasons for this, including lack of knowledge about how to conduct PAGP, as well as the long tradition of individualistic approaches to psychotherapy in general. The implementation of PAGP into the healthcare system at psychiatric hospitals is also difficult because it requires a great deal of coordination, attention and specific knowledge about PAGP that is different from other current practices.

Structural challenges

Some difficulties that PAGP brings may be avoided in the individual setting, one of them being the more rigid procedures. In comparison to the individual approach of IPAP, in which one or two therapists accompany one patient, our experience showed that in PAGP there can be up to four therapists who may be guiding a group at a time. The group environment may thus seem impossible to predict at first. For it to not become laborious or chaotic, it is important to outline a code of conduct and specific rules to which every participant must agree. It is therefore essential to establish a balance between individual and group processes, which requires good choices about which patients to include. Time management and session schedules are less flexible, and therapists must be mindful of individual needs regarding stillness, talking and movement, as well as substance-related openness. However, given a strong group cohesiveness, experienced PAGP members tend to actively maintain boundaries and group rules in a mostly calm and open manner, which should be encouraged. Faced with this challenge, Spencer (1963) at first allowed the patients to freely do as they wish during the psychedelic sessions, stating that

Certainly the patients in this group needed to pass through a phase in which they could do exactly as they wished and still retain the therapists’ love before they could pass on to a more mature phase of accepting the demands of society upon them.

During psychedelic sessions, coordinating individual differences in dose and effect may be laborious, as well as disturbances due to noise and restlessness. In general, we can say that a higher degree of illness requires more active guidance of the patient. However, it also can be especially difficult to integrate distinctly egocentric individuals within the group. Generally, there is also the concern of patients being less open in the group setting compared to the individual setting, as they could be worried about other people’s reactions during the session. This could lead to interferences or a loss of focus within the intrapersonal process.

Challenges with therapeutic factors

Challenges related to PAGP are similar to those found in conventional group therapy. Before starting therapy, therapists should carefully screen patients to determine eligibility. External factors, such as acute stress or moving, can lead to early dropout (Yalom, 1966). It is also important to not create false expectations that the therapy is beneficial for everyone, as some patients may prefer individual therapy or request a disproportional amount of personalized attention.

A lack of universality can sometimes lead to ‘early provocateurs’ (Yalom, 1966), who exhibit aggressive behaviour and then leave due to anxiety. Others may develop a feeling of not fitting in, which is called group deviancy and is accompanied by a lack of psychological sophistication and interpersonal sensitivity. This can damage the group cohesion process if not addressed by the therapist. Providing individual sitters for these patients can help them feel supported.

Without the corrective recapitulation of the primary family group, problems with intimacy may arise, such as schizoid withdrawal, maladaptive self-disclosure or unrealistic demands for ‘instant intimacy’ (Yalom, 1966). When socializing techniques are not developed with the guidance of the therapist, complications can also arise through subgrouping, in which patients who feel left out create their own subgroups within the therapy group, damaging the group cohesion process.

Interpersonal learning processes can be disturbed when patients are strongly affected by hearing the problems of other group members, causing fear or upset. This can have a lasting impact on the group atmosphere, and therapists should address these reactions individually and encourage an accepting mindset within the group.

Another point addressing the interpersonal exchange in PAGP is that some authors have argued that psychedelic experiences can seem ineffable (Nielson et al., 2018; Nielson and Guss, 2018; Pedersen et al., 2021). They can be vastly different not only inter- but also intra-individually, potentially creating a greater feeling of isolation or uniqueness amongst group members rather than the desired therapeutic outcome. This especially concerns difficulty describing the experience in integration sessions, but also portends difficulties with properly informing naïve patients about what they can expect in a psychedelic session (Johnson et al., 2008). It therefore generates considerations regarding the correct preparatory approach of set and the establishment of a shared vocabulary. More research on PAGP is needed to identify the most beneficial therapeutic context to introduce the psychedelic group experience to the patient. Focusing more closely on the influence of an interpersonal setting on psychedelic intake may shed light on further therapeutic factors.

Depending on numerous variables in patients’ predisposition, dosage, set and setting, the ‘peak psychedelic experience’, meaning the moment the effects are perceived to be the most intense, is not always pleasant (Passie and Dürst, 2008). ‘Bad’ or ‘challenging’ experiences endure critical discussion about their therapeutic efficacy, as some argue that they can lead to therapeutic benefits, and others point out that they can have the potential to be damaging or provoke undesirable changes in core beliefs (Carbonaro et al., 2016; Greif and Surkala, 2020; Roseman et al., 2018b). This may lead the patient to lose hope with the therapy approach or create disturbances within the group. An essential aspect of PAGP is that challenging experiences are well supported as they happen, as well as thoroughly discussed in a social setting after they subside. Giving psychedelics too frequently without sufficient integration of the experience into daily life may also result in delusions and disappointment in the long run (Oehen, 2013).

Finally, we echo some problems mentioned in an earlier PAGP study (Spencer, 1963). Treating all patients in the group equally is important to lessen the feeling of uniqueness and strengthen the group cohesiveness. Adding to this, not all participants will always be willing to participate in the group process, which can affect the therapeutic factors in general. Lastly, therapists need to be prepared for the potential physical acting out of a cathartic expression.

The therapists’ self-experience with psychedelics

In the 18th and 19th centuries, clinicians were encouraged to have self-experiences with psychoactive substances before administering them to patients. In contrast to such controlled self-experiments, today’s scientific experiments that are more carefully designed often do not provide enough detailed information about the subjective experiences (Passie and Brandt, 2018). However, therapists must understand the psychoactive effects to know how to convey psychedelic therapy to their patients. If a therapist expects overly idealistic outcomes from the work with psychedelic substances, he or she may not only overstrain the patient, but also abandon the attitude of a supportive psychotherapist (Noorani and Martell, 2021). In conveying the particular nature of PAGP, we argue that the therapist can gain the most accurate knowledge of how to understand and describe the complexity of psychedelic states by experiencing psychedelics themselves. In the same way as any psychotherapist has the duty, ethically and administratively, to have undergone psychotherapy, we believe that a PAGP therapist would benefit from their own supervised psychedelic intake in a therapeutic group setting, which should be part of the obligatory psychotherapeutic training (Gasser, 2022; Oehen, 2013). As Oehen and Gasser (2022) have stated, ‘In our view, psychedelic therapists should have experienced drug-induced altered states of consciousness in a therapeutic setting themselves in order to fully appreciate and understand the mechanisms of action, possibilities, limitations, and pitfalls of the process’.

Since a great deal of the psychotherapy work revolves around promoting the patient’s self-reflective and self-regulating skills, psychedelic therapists will be better able to guide the patient in discovering and understanding how their mind works if they can refer to their own subjective experience. This is even more important when dealing with psychotherapies that used altered states of consciousness, like IPAP and PAGP. This is also the case for mindfulness-based CBT, which is based on the patient learning meditation techniques. The mindfulness therapist in training is asked to practice mindfulness meditation and learn from personal experience in order to be able to best implement this therapy and understand patients’ experiences with it (Crane and Kuyken, 2013). In addition, patients in altered states of consciousness sometimes pick up on extremely subtle cues to the therapist’s current mental state. A therapist who is not authentic and aware of his or her own weaknesses and unresolved issues will not always be able to fool patients, which may get in the way of the therapeutic process (Oehen, 2013).

However, therapist experiences with psychedelics may not be currently feasible, since psychedelics are still scheduled as dangerous, illegal drugs under the UN Conventions and many governments’ drug laws (Nutt and Carhart-Harris, 2021). Nowadays, an aspiring psychedelic psychotherapist could feel forced to do something that is illegal or at least stigmatized, even in countries with legal psychedelic drugs (Nielson and Guss, 2018). If there is no access to an organized therapeutic setting, taking psychedelic substances alone risks either overburdening the therapist or being perceived as superficial. Guided psychedelic sessions in an illegal context could also create a stigma from the patient perspective, as they may worry about their therapist engaging in illicit activities, which could negatively impact trust and the therapeutic alliance (Nielson and Guss, 2018).

There have been only a few documented cases of psychedelic sessions conducted within a therapist training program. In the 1970s, one study examined 203 mental health professionals undergoing experiences with LSD as a part of their training in the United States. However, the data were never systematically analysed or published (Nielson and Guss, 2018). Individual therapist experiences have been documented within the MDMA-assisted therapy training from the Multidisciplinary Association for Psychedelic Studies, and those therapists reportedly felt more prepared to conduct their therapy sessions (Nielson and Guss, 2018). Further research into therapist efficacy is needed to evaluate this result. Regarding PAGP, one psychedelic therapist training at the Imperial College London has successfully piloted a study on potential psychedelic therapists undergoing a voluntary group experience with psilocybin (Nutt and Carhart-Harris, 2021). These are first steps towards a wider acceptance of guided psychedelic sessions in a PAGP therapy training program, but more research into outcomes from these trainings is needed.