The use of the psychological flexibility model to support psychedelic assisted therapy

This theory-building paper (2020) presents the ACE (Accept, Connect, Embody) model and how it’s being used in a trial (Psilodep 2) with psilocybin-assisted therapy for depression.


“Psychedelic assisted therapy comprises three stages: Preparation, Psychedelic Session, and Integration. Preparation is key for maximising the potential of a beneficial psychedelic experience and integration is important for prolonging improvements. The psychological flexibility model (PFM) appears to be a promising one to guide psychedelic preparation and integration. This paper proposes a model that utilises the PFM as informed by a previously published qualitative study of patient accounts of change processes in psilocybin therapy that identified themes of acceptance and connection as associated with positive outcomes. This new model, the ACE (Accept, Connect, Embody) model presents the six psychological flexibility processes, renamed and rearranged in an acceptance triad (defusion, present moment focus, willingness) and a connection triad (self as context, values, committed action). This paper describes the ACE model and how it is being used in an ongoing trial of psilocybin treatment for major depression. It also describes qualitative evidence supportive of the idea that psychological flexibility may be key to characterizing the processes of change involved in psilocybin assisted therapy for depression. These and other results suggest that psilocybin may be specifically increasing psychological flexibility and point to the possibility that psychotherapy approaches incorporating the PFM may serve as a means to deepen and extend the benefits of psilocybin treatment, thus bridging the experiential gap between a potent inner experience and an outer life better lived.”

Authors: Rosalind Watts & Jason B. Luoma


Highlights from the authors:

  • “The psychological flexibility model can be used to guide psychedelic-assisted therapy
  • A new model, the ACE (Accept, Connect, Embody) model, is outlined
  • The paper describes how this new model is being used in a psilocybin trial
  • Qualitative data is re-analyzed in terms of psychological flexibility processes”


Psychedelic assisted therapy comprises three stages: preparation, psychedelic session, and integration. The psychological flexibility model (PFM) appears to be a promising one to guide psychedelic preparation and integration, and the ACE model (Accept, Connect, Embody) is being used in an ongoing trial of psilocybin treatment for major depression.

Psychological flexibility is a model that can be used to support psychedelic assisted therapy. Psychedelic experiences can be of positive, negative, or both positive and negative valence. A new model called Accept Connect Embody (ACE) was developed based on experiences and data emerging from the Psilodep 1 trial, which involved 20 people with treatment-resistant depression.

The ACE model provides support in preparing for and integrating psychedelic experiences. It includes a diagram that renames and rearrages six flexibility processes based on clinical experience and previous qualitative research. The ACE model is being used in a second trial of psilocybin therapy for major depressive disorder, and provides a framework for therapists to guide patients towards acceptance of what is challenging, connection to what is positive, and staying embodied.

Preparation is essential to help people approach the psychedelic experience with as little resistance as possible, and integration helps patients process the events that occur during psychedelic sessions, learn valuable lessons from them, and incorporate key lessons into their daily life. Psychological flexibility and psychedelics can open people up to long suppressed feelings both negative and positive. These experiences can feel like they are going to change things forever, but then people return to their “old lives”.

Psychedelics can introduce a valuable burst of flexibility in the short term, but long term behaviour change is difficult to achieve. The psychological flexibility model can be used to guide the preparation and support for integration of psychedelic experiences.

Contact with the present moment encourages us to focus on our sensory experience and accept our unwanted feelings, while acceptance encourages us to see through our thoughts.

Psychological flexibility is the ability to contact the present moment more fully as a conscious human being and to change or persist in behaviour in order to serve valued ends. Psychological flexibility has been shown to be an important therapeutic target across numerous studies. Although numerous techniques are available from Acceptance and Commitment Therapy and other approaches to increase psychological flexibility, many people still not helped by psychotherapy.

Qualitative data obtained from participants in Psilodep 1 were consistent with the idea that increased psychological flexibility is an important route through which psychedelic administration has beneficial effects. Thematic analysis identified two main themes reflecting a process of movement from disconnection to connection and from emotional avoidance to acceptance. Below we share patient accounts of psilocybin use that demonstrate the six flexibility processes. These accounts also illustrate how the PFM might apply to psilocybin use as a treatment for depression.

People with depression get stuck in mental loops, replaying the same mental content again and again, often with a highly negative and self-critical content. Psychedelics can overcome these mental loops by creating an intensely emotional, moment-by-moment, sensory quality of experience. Psilodep 1 participants described feeling freer from mental traps, and having a greater sense of mental clarity that persisted for several months.

Participants described feeling more embodied, sensorially alive, and present after taking psilocybin, both during sessions and afterwards. They felt more grounded, also more calm, and their natural state is the opposite of mindfulness – its mindlessness.

Patients experienced intense emotional states that were overwhelming at times, but were also a sense of confronting difficult experiences.

Patients reported being able to more fully experience and embody long suppressed or traumatic experiences during the psilocybin experience, and emerging with a greater openness to their own emotional experience. I was crying a lot, crying with relief, and I was confronting suppressed experiences, visions, memories. It was a great letting go, a great purging, and I took away the knowledge that I can have anxiety.

Some patients reported a more positive sense of self following psilocybin treatment, and an experience of interconnection with the world.

Many participants reported shifts in their sense of self following treatment, including a return to past valued activities or making major lifestyle changes. They were able to access expanded aspects of self, including an observer self, teacher self, wise self, and a loving/compassionate self. I had an encounter with a being that told me it’s alright, I don’t need to be sorry for all the things I’ve done. I felt true compassion towards myself.

I had my eyes closed, I didn’t feel that the observer was changing, I was still there, and I got a wider perspective, I stepped back, and I felt like everybody, unity, one life with 6 billion faces. Patients who had suffered depression for a mean of 18 years reported feeling connected to their values and being enthusiastic again. They described a reorientation in their values toward interconnectedness of humans with each other and with nature.

People who have taken psilocybin have accessed new perspectives and revelations that helped them turn insights and understandings into actions. Examples of committed action include: not eating land animals, not eating eggs from a chicken, and looking at trees as living things with spirit. The dose helped me understand my goals, gave me the motivation and clarity to do something, so I immediately signed up at the gym and put myself into the job world. I lost a lot of weight because I couldn’t eat badly and I couldn’t watch pornography after the second dose. I made good new friends that share my values.

I went to a bike shop and helped renovate it for 6 months, because I wanted to do good things.

Neuroscientific data suggests that psilocybin induces a flexible brain state, which can disrupt entrenched beliefs. This flexible brain state can feel like the mind is opening up. Psilocybin can temporarily disrupt the old grooves in the snow, setting up the possibility of new tracks being laid down. However, these new habits need to be practised in order to consolidate the new learning.

The ACE model emerged from Psilodep 1 and is being applied in Psilodep 2, a registered randomised double-blind clinical trial in which patients undergo two psilocybin sessions, four preparation sessions, two psilocybin sessions scheduled three weeks apart, and 4-7 integration sessions. The integration portion of Psilocybin 2 consists of 4 sessions, 1 week after Psilocybin 1, 2 weeks after Psilocybin 1, and 3 weeks after Psilocybin 2.

Psilocybin therapy is a non-directive therapy model that relies on the patient to feel into bodily sensations rather than distract from them, accept rather than avoid anything difficult, and communicate key experiential themes with the therapists without talking so much that the felt sense is disengaged. The Psilodep 2 model is based on the assumption that the patient’s inner intelligence has a benign trajectory, and that any material that arises in the psyche in a non-ordinary state of consciousness will be precisely what is required for the person’s move towards wholeness.

The ACE principles are intended to support a naturally unfolding process, rather than to direct it. Patients have reported that they prefer a client-centred and non-directive approach to therapy. The ACE model is a theoretical framework for guiding the preparation and integration sessions in Psilodep 2. It is based on clinical experience, qualitative data from Psilodep 1, training provided by William Richards and Tim Read, and discussions in the London Psychedelic Integration Group.

The ACE model represents the view that acceptance and connecting to meaning are both equally important.

Patients with depression often describe living in their heads in a state of numb despair. Psilocybin sessions often bring up repressed emotions, both negative and positive. The ACE map represents the essential polarity of lived experience: the light and the shadow. The Embodiment aspect runs all the way through and acknowledges the limitations of “talk” therapies that neglect embodied experience. Using the ACE model for psilocybin preparation, the direction is from the lower (blue) part of the map to the upper (pink) part, where full, embodied acceptance of pain can elevate it into meaning.

The first part of the session involves sharing information about psilocybin with the patient, who is encouraged to welcome the challenge, go towards anxiety rather than away from it, and trust, let go, be open. Psilocybin sessions are an opportunity to practice what could become a new attitude to life more generally. Patients connect with the idea that their sessions are an opportunity to face monsters that they have been running from their whole life. The patient lies back on the couch they use during the psychedelic session, wears eyeshades, and listens to the guided instructions for an experiential visualisation exercise.

As the patient swims down through deep waters, they conduct a body scan, and then open the spikiest oyster shells to find the pearl of wisdom (metaphor for accepting pain rather than avoiding it). They use the insight to broaden their selfconcept and set intentions for the session the next day. The P-ACE is an interactive therapy that requires the participant to practice getting into contact with emotions whilst in the presence of two relatively unknown therapists. The therapist holds the patient’s hand and demonstrates an attitude of acceptance and connection towards the patient at all times.

The body scan component of the P-ACE helps patients relax and develop awareness of the felt sense of their body and how this corresponds to their emotional state. The importance of willingness to experience is prioritised in a non-threatening way. Before a psychedelic session, patients are led to identify the reasons why the session is needed, their hopes about it, and their overall goal. These intentions feel authentic, as they emerge from a process of both feeling and thinking rather than from thinking alone.

Psychological flexibility and psychedelics can be experienced as beyond words and one’s normal experience. The therapist’s task during integration is to help bridge the gap between the lessons of the psychedelic experience and the ongoing life circumstances of the participant. In Psilodep 2, patients are supported in sharing as much of their experience as they can, while also distilling key insights and supporting behaviour change. The therapist provides support in developing their narrative, and is expected to map their level of activity to the needs of the patient.

The therapist focuses on witnessing the participant’s experience with a high degree of presence and validation, and feels deep respect as the participant relays more details of all they have seen and felt. The therapist helps the patient deal with the themes relating to an absence of accurate empathy in early life by providing validation, facilitating reflection on the key aspects of the experience, and assisting the patient in identifying new behaviours and goals.

The psychological flexibility model informs the whole integration process, and the I-ACE exercise helps patients learn a skill for managing negative thoughts and emotions when they return. The I-ACE is similar to the P-ACE, except that the final stage asks for intentions around pursuing life goals rather than intentions for the session. Patients can use the I-ACE diagram to maintain their new flexible way of approaching life.

The PFM model recognises the traps of language and tries to target the excesses of language to enhance psychological flexibility. Psychedelics offer a route to embodied awareness and the relief and learning this can bring, and can potentially enhance psychological flexibility more intensely and without verbal instruction. This paper outlines how the PFM model can be used to guide psilocybin assisted therapy for depression, and how the resulting model, called ACE (Accept, Connect, Embody), is being utilised in an ongoing clinical trial.

Psychedelics have been shown to increase openness and increase the personality domain of openness in people who have experienced them. This article discusses the research on psychedelics and smoking cessation.

Roemer, Salters, Raffa, and Orsillo (2005) tested a conceptual model for anxiety disorders based on fear and avoidance of internal experiences.

Vowles, Witkiewitz, Sowden, G., Ashworth, J. (2014). Acceptance and commitment therapy for chronic pain: Evidence of mediation and clinically significant change following an abbreviated interdisciplinary program of rehabilitation.

I invite you to close your eyes, steady your breathing, and focus on your nostrils as you breathe in and out slowly.

Imagine a vast ocean early in the morning, the sun is rising over the surface of the sea, and you are picking up some diving equipment. You take a deep breath, look around, and then climb down a ladder and lower your body into the waters. Imagine yourself bobbing about on the surface of the sea, and then you take a deep breath and dive deep down. You are completely safe as you dive down into the warm water, and you can breathe so easily and feel held, supported and warm as you swim down.

As you dive down towards the sea bed, swish your awareness over your whole body: fingers, hands, forearms, upper arms, shoulders, neck, face, top of head, back of neck, upper back, chest area, heart area. Stay here for some heart breathing, and then breathe into your stomach, thighs, calves, feet, toes, and then breathe out through your mouth, letting it all go. If you have any uncomfortable sensations in your body, don’t try to distract or avoid them, instead try to really feel them. You are diving deeper in the ocean, and there are many different directions you can go in. There are bright corals and beautiful exotic fish in some directions.

Be carried by your willingness to experience everything fully. Let go of expectations and requirements of yourself, and embrace the opportunity to see and feel things you’ve never seen before. When you swim down to the sea bed, search your hands through the mud, feel it to its depths, and then go right into the pile of spiky ugly oyster shells, let yourself feel them, every rough angle, and then go forwards, facing the hard feelings. If you can identify 40 difficult memories or feelings, imagine that each one of those emotions is an oyster shell. List all the emotions you can feel and let me know what they are. When you make space for emotions, you are opening up the oyster shell. Stay with the first emotion and really feel it, then move on to the second emotion. When you open up an oyster, a little bit of grit gets inside the shell, and the oyster responds by coating the grit with mother of pearl. The pearl turns the grit into something precious, and the lesson in the pain is the pearl.

When you feel your emotions fully and search for the meaning in them, you are searching for pearls of meaning that tell you something about what really matters to you. When you have this pearl in your hand, swim up through the water towards the sky, with great energy, kicking your legs, and notice how your body feels as you do so. Suddenly there is great calm, the water is still, and the boat is there waiting for you. You climb aboard the boat, sit on your comfy chair, and gaze at the rising sun. Then you open the door to the sea.

When you got home, you looked at the pearls you brought with you from the oyster shells and thought about how this experience might inform an intention for the psilocybin session tomorrow.

I-ACE Script invites you to close your eyes, steady your breathing, and focus on the tip of your nostrils as you breathe in and out. This is an exercise for you to do regularly to stay in contact with how you are feeling. Step 2: Lie down on your front, with your arms outstretched, and scan your body from tips of your fingers to your toes. Note any tight spots, or spaciousness, any tenderness, tensions, uncomfortable or enjoyable sensations. Step 3: Search around for spiky oysters, open them gently, and feel the emotion within. If there are other oysters, open them and feel the positive emotions within.

When you have felt all the emotions you feel right now, search the oysters for pearls. Reflect on the main emotions you have felt, and what they teach you about what matters to you. Step 4: Swim up to the surface, take a big breath, and gaze at the sun. Know that you are the sea, the great depths, heaviness, the physical body, emotions, and the sky, the expansive sky that holds them all. Step 5: Look at the pearl you found in the oyster and put into words why this matters to you.

Step 6: Make a promise to yourself to honour the work you have done with an action. This action can be something very small that you will do today, in service of this pearl you have found.

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Theory Building