Using a MDMA- and LSD-Group Therapy Model in Clinical Practice in Switzerland and Highlighting the Treatment of Trauma-Related Disorders

This study (2022) examines the group therapy model used in MDMA and LSD therapy in private practice in Switzerland. The majority of patients suffered from PTSD with psychedelic therapy addressing symptoms like regulation of emotions and impulses, negative self-perception, alterations in relationships with others, as well as meaning, recall, and processing of traumatic memories. MDMA was most often used in the first phase to enhance motivation to change while LSD was introduced to intensify and deepen the therapeutic process.


“The Swiss Federal Act on Narcotics allows for the restricted medical use of scheduled psychotropic drugs in cases of resistance to standard treatment, and preliminary evidence of efficacy of the scheduled drug for the particular condition. Since 2014, the authors have obtained 50 licenses on a case-by-case basis and developed a psychedelic-assisted group therapy model utilizing MDMA and LSD. The majority of the patients taking part in the psychedelic group therapy suffered from chronic complex post-traumatic stress disorder (c-PTSD), dissociative, and other post-traumatic disorders. Treatment modalities, typical developments and problems encountered during and after the psychedelic experiences are described. Recurrent depression poses a frequent problem, and requires special attention. Symptoms of c-PTSD predominantly addressed by the psychedelic experiences are the regulation of emotions and impulses, negative self-perception, alterations in relationships with others, as well as meaning, recall, and processing of traumatic memories. C-PTSD needs a larger number of psychedelic experiences in contrast to PTSD resulting from a single trauma. In this model MDMA was most often used in the first phase to enhance motivation to change, strengthen the therapeutic alliance, allowing it to become more resilient, stress-relieved and less ambivalent. When emotional self-regulation, negative self-perception and structural dissociation had also begun to improve and trauma exposure was better tolerated, LSD was introduced to intensify and deepen the therapeutic process. The majority of participants improved by clinical judgement, and no serious adverse events occurred. A short case vignette describes a typical process. The experiences with this model can serve to further develop the method of psychedelic-assisted psychotherapy (PAP) and to give directions for future research.”

Authors: Peter Oehen & Peter Gasser



Since the discovery of LSD in 1943, several attempts have been made to prove the effectiveness of psychedelics as adjuncts to psychotherapy. Most of these studies do not meet modern research standards and are therefore of limited validity.

After its introduction into psychotherapy in the late 1970’s, MDMA rapidly spread as a recreational drug. However, clinical research has shown that MDMA can be used to treat social anxiety with autistic adults and treatment-resistant post-traumatic stress disorder.

All studies on psychedelic psychotherapy used an individual setting with one or two sitters/therapists per patient. The only documented exception to this rule took place in Switzerland from 1988 to 1993, when a small number of psychiatrists in private practice used a group setting.

This article describes the use of MDMA and LSD as adjuncts and catalyzers of psychotherapy in a mixed clinical population of patients who did not respond to standard treatment, using a group model.

In the United States and some other countries, a program called Expanded Access was approved by the FDA in 2019 for people facing a serious or immediately life-threatening condition.


The Swiss Federal Act on Narcotics and Psychotropic Substances allows for the restricted medical use of scheduled psychotropic substances, if existing treatments are ineffective and preliminary scientific evidence suggests the efficacy of the drug for the particular condition.

Since the Swiss MDMA/PTSD study and the Swiss LSD/anxiety in life-threatening disease study results were published in 2013 and 2014, several patients from outside Switzerland have requested psychedelic-assisted psychotherapy in Switzerland.

In a first phase, MDMA and LSD were administered in an individual setting to patients with trauma-related disorders. In a second phase, a psychedelic-assisted group therapy model was established.


The focus of referrals and requests for therapy in the first author’s practice shifted increasingly toward trauma-associated disorders, and the group setting did not meet the specific needs of the cluster headache/migraine subgroup.

We treated 50 patients between 2015 and 2020, of whom 21 had trauma-related disorders, 12 had comorbid depression, and 2 had ASD.

Inclusion Criteria

Treatment-resistance in depression and anxiety disorders was defined as not responding to at least 2 antidepressants, augmentation strategy and psychotherapy.

All patients participating in psychedelic-assisted psychotherapy had to be in regular psychotherapy with one of the authors. They also had to agree to a professional exchange between all therapists involved in the treatment.

Exclusion Criteria

Borderline personality disorder (BPD) was excluded as an index diagnosis, and c-PTSD patients with comorbid borderline personality traits were carefully assessed before being accepted for psychedelic-assisted psychotherapy.


MDMA and LSD were provided by the Pharmacological Department of the University Hospital of Basel, Switzerland. Psilocybin has also become an option since 2020.

Choosing Substance and Dose

All psychotropic medications were discontinued at least five half-lives before the psychedelic-assisted sessions. All somatic medications were continued.

MDMA was indicated for the first phase of psychedelic-assisted psychotherapy because of its easier to handle effects, its anxiolytic and prosocial properties, as well as to enhance motivation to change, strengthen the therapeutic alliance and become more resilient.

LSD was indicated for later stages of therapy, when trauma processing had already taken place, and exposure to traumatic material could better be tolerated. The dose of LSD was titrated over the first few sessions, depending on the target symptoms, personality and psychological defense structures.


Our model is based on the theory that traumatization begins early in life and leads to developmental constraints, pathologies, and/or specific trauma-related disorders. We use psychedelics to treat trauma by restoring healthy network connectivity.

To fully understand the effects of psychedelic therapy, therapists should have experienced drug-induced altered states of consciousness themselves.

Complex Post-traumatic Stress Disorder

Herman first proposed the concept of complex post-traumatic stress disorder (c-PTSD) in 1992 to describe the multifaceted symptoms of traumatized patients who suffered repeated or prolonged physical, sexual and/or emotional abuse and neglect during childhood and adolescence.

Despite its clinical usefulness, c-PTSD was not included in the DSM-5 revision. In contrast, it was included in the ICD-11 revision as a distinct condition.

We followed the ISTSS guidelines for the treatment of cPTSD, which differentiated eight symptom clusters, including three core symptoms of PTSD, and five clusters of symptoms associated with impaired self-regulatory capacities.

The recommended model for treatment for c-PTSD consisted of three phases: stabilization and skills strengthening, trauma processing and integration, and transition to everyday life.

The major existing and empirically supported, effective trauma-focused psychotherapies include psychoeducation, emotion regulation and coping skills, exposure to traumatic memories, cognitive processing and restructuring and/or meaning making, and trauma narrative creation.

Preparatory phase

A trauma-focused psychedelic-assisted psychotherapy was conducted with patients with cluster headache, end-of-life issues, or ASD. Individual sessions were conducted with patients with a strong fear of the psychedelic experience itself or a pronounced fear of the group situation.

Psychoeducation, establishment of a therapeutic relationship and alliance, learning basic skills for awareness and regulation of emotions, and formulation of a tentative working hypothesis are all necessary before psychedelic-assisted psychotherapy can begin.

Group Procedures

The psychedelic-assisted group sessions took place four times a year in a quiet residential area on the outskirts of a small town in Switzerland. There were twelve participants and three therapists, of which one was female.

MDMA experience is shorter than LSD experience and participants should refrain from direct interactions with other group members during the opening and plateau phases of the experience.

Two authors alternated in the role of main guide, and two other authors acted as co-therapists/sitters.

Participants met in the evening before the psychedelic experience for 3 h, during which they warmed up, discussed recent developments, problems, expectations, concerns and fears, and set intentions for the next day. The therapists answered questions about dosage, effects and procedures, and gave instructions on how to appropriately manage the altered state of consciousness.

On the day of the psychedelic experience, the group would meet at 9.30 a.m. to discuss last minute questions and concerns. The ingestion of the substances took place at about 10 a.m. Music and silence/stillness alternated, and the main guide repeated instructions or suggested some body awareness exercises.

We played music for one third of the session, while two-thirds of the process took place in silence. The music was carefully selected according to its intended effects on the group and the individuals.

The therapists monitored participants, moved around the room, and sat with them spontaneously and on request. They avoided lengthy verbal exchanges and offered touch to help the patient overcome avoidance and resistance.

After ingestion of the substance, participants were asked to express how they were feeling and give short statements concerning what they had experienced so far.

We served a light dinner to the participants and closed the group session at 7 p.m. Participants could stay together for the rest of the evening.

The group met again on the final day at 9.30 a.m. to discuss the experience in detail. This integrative talking session took about 4 h and terminated with final instructions for the following time on what to do in case of an emotional crisis.

All participants were required to write a comprehensive report of the experience and fill out the 5D-ASC and MEQ questionnaires.

Development of the Group as a Whole

From 2014 to 2020, 22 group sessions took place. Participants with trauma-related disorders, anxiety disorders and depression required a lengthier individual and group therapeutic process, whereas participants with cluster headache required a more short-term symptom reduction.

Over time, a core group of participants formed that met outside of the therapy sessions and provided mutual support. They also helped newcomers experience secure attachment, mutual responsibility and care for each other.

As in every group, conflicts later arose, for example from transference. We advised participants to declare conflicts before the experience, so they could focus on their own part of the conflict and try to resolve it during the last phase of the experience.

Typical Individual Developments Treatment Modalities and Outcomes

Table 2 shows that 35 out of 50 patients attended only group sessions, and 9 out of 50 patients attended both group and individual sessions. The most frequent diagnosis being c-PTSD, a typical pattern of the therapeutic process was distinguished in this subpopulation. The first psychedelic-assisted sessions were usually very trying for all involved, with the positive and pleasant effects of MDMA being followed by the confrontational phase with direct recall of traumatic material and intense negative emotions.

A complete process of recollection of trauma could take one to a lengthy series of psychedelic-assisted sessions, depending on how early in life the traumatization took place and how extensive it was.

After a certain number of sessions, patients kept reliving similar traumatic events without gaining any further benefit from this confrontation. This was a reason for switching from MDMA to LSD.

The outcomes of 50 reported psychedelic-assisted therapies are presented in Table 3. Outcomes were determined by clinical judgment.

The major symptom clusters of complex post-traumatic disorder were attenuated in all 21 patients. Four patients achieved remission, 13 improved, three did not improve, and two patients with anxiety disorders remitted, five improved clinically, and three did not improve.


Pre-existing antidepressant medication was a problem for which there was not yet a good or consistent solution available. Two patients experienced “a strange trip” and the dose of their antidepressant medication was lowered but not stopped because of these difficulties.

Patients with depression or PTSD who discontinued antidepressant medication before the psychedelic experience tended to relapse after the experience. However, after two or three episodes, individual cues could be identified which allowed for the timely reinstallation of antidepressant medication.

Adverse Events, Difficult Situations, Discontinuation of Treatment, and Conflicts in Group

Another 38-year old woman who had used high doses of analgesics and ketamine nasal spray for acute headache attacks attended one group session with LSD 100 mcg.

During the acute drug effects, nobody tried to leave the premises, but some patients wanted to sit outside on the balcony or be alone in the annex room. Heavy smokers wanted to go outdoors to smoke, but this had not been part of the agreement.

Patients with comorbid borderline traits tended to have more difficult psychedelic experiences that required more support from the therapists. They also received more understanding, compassion and often “co-therapeutic support” from fellow patients.

Early termination of treatment happened in two cases because patients did not comply with the agreements of the treatment, and one case because a patient had a conflict with one of the therapists.

Case Vignette

Anne, 51, had followed continuous treatment with antidepressants for many years, and had two adolescent children. She began three extensive courses of psychotherapy, but her traumatic childhood remained unaddressed.

Anne grew up in a frosty family atmosphere with a sadistic, hot-tempered, violent and unpredictable father who abused both Anne and her sister sexually. Anne still feels responsible for her sister’s BPD and eating disorder. The repeated witnessing of her sister being sexually abused, the prolonged physical and emotional neglect and the massive guilt conflict led to deeply rooted emotional and relational problems, negative self-perception and low self-esteem.

She was diagnosed with chronic depression and PTSD, and was able to enhance her awareness of the constant distress and avoidance patterns that she had been experiencing for decades.

After more than 1 year of intensive psychotherapy, the patient had her first MDMA experience in a group setting. She felt great relief about finally being able to speak freely about her father’s abuse of her sister and gaining trust and self-esteem.

In the group, she befriended a fellow patient and developed a sister-transference reaction to her. This helped her gain independence, self-worth and authenticity.

During the integrative therapy, she needed reassurance and confirmation of her perceptions and behavior in a childlike manner. Then, after an impressive and overwhelming death-rebirth experience under LSD, she was able to change her habitual negative self-perception and become increasingly self-confident, assertive, more independent, self-determined and resilient. After the first few MDMA experiences, she was able to forgive her father and have a closer relationship with her mother. Her marriage and children also improved during this phase.


Anne’s psychedelic-assisted psychotherapy included an extensive psychoeducational preparation phase, a lengthy and intense drug-initiated phase of recall and processing leading to a coherent trauma narrative, and cognitive restructuring.

MDMA increased Anne’s change motivation, perseverance and emotional window of tolerance substantially, as well as decreasing the degree of post-traumatic avoidance. LSD addressed the deeply rooted relational, attachment and self-relational problems.


Based on modern psychodynamic and psychotraumatological concepts, as well as on the preliminary empirical evidence for psychedelic-assisted psychotherapy, a model of group psychedelic-assisted psychotherapy for a population of patients with a variety of diagnoses is presented.

Administering LSD and MDMA in the same group requires careful dosing, consistent structuring and guiding of the group process, and allows for more efficient treatment of patients in the given time. There are no safety problems and no serious adverse events requiring hospitalization.

The outcomes presented here are purely descriptive, based solely on clinical judgement, and have limited significance. However, the practical experiences can provide directions for future research.


The study did not require ethical review or approval, and all participants provided written informed consent.

Study details

Compounds studied

Topics studied

Study characteristics
Commentary Theory Building

54 Humans


Authors associated with this publication with profiles on Blossom

Peter Gasser
Peter Gasser has done work on LSD and life-threatening diseases in Switzerland since 2008. He is a psychiatrist, psychotherapist, and study lead, working in private practice.

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Group psychedelic therapy: empirical estimates of cost-savings and improved access
This economic analysis (2023) from two psychedelic therapy trials (MDMA-PTSD & psilocybin-MDD) with group and individual therapy aims to assess clinician time, costs, and patient access. Group therapy demonstrated cost savings of 50.9% for MDMA-PTSD and 34.7% for psilocybin-MDD, potentially reducing the need for full-time equivalent clinicians by 6,711 for MDMA-PTSD and 1,159 for psilocybin-MDD in the U.S., leading to projected savings of up to $10.3 billion and $2.0 billion, respectively, over ten years. Adopting group therapy protocols is suggested to enhance efficiency, reduce costs, and address the shortage of trained clinicians, thereby improving access to psychedelic-assisted therapies.

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