How People Experience Psychedelic Treatments for Eating Disorders: A Summary of Qualitative Studies

Eating disorders (EDs) are complex psychiatric disorders characterised by disturbances in eating- and weight-related perceptions, thoughts, emotions and behaviour, and severe psychological and physical complications, with a biopsychosocial pathogenesis [1]. The 11th edition of the International Classification of Diseases (ICD-11; [2] recognises several EDs, such as anorexia nervosa (AN), bulimia nervosa (BN), binge eating disorder (BED), avoidant restrictive food intake disorder (ARFID), pica, rumination-regurgitation disorder, as well as unspecified and other specified feeding and eating disorders (UFED, OSFED). AN can be further classified by sub-type according to the presence or absence of binge eating and compensatory behaviours; termed the binge-purging and restrictive subtypes, respectively.

EDs are associated with rigid thought and behavioural patterns and deficient cognitive functioning and flexibility. There may be difficulty naming, regulating, and experiencing bodily feelings and emotions [3]. EDs are often described as coping mechanisms to help control and deal with underlying unmanageable emotions (e.g. depression, anxiety; [4]). Moreover, individuals with EDs often report previous challenging interpersonal or traumatic experiences [5]. Yet, EDs are more complex than the characterisations and symptoms listed here; these are complex psychiatric disorders with severe comorbid psychopathology [6], impairment across various domains [7, 8], and high mortality rates [9].

The National Institute for Health and Care Excellence (NICE) recommends psychological therapies as first line interventions for EDs [10]. These include eating-disorder-focused cognitive behavioural therapy (CBT-ED), Maudsley anorexia nervosa treatment for adults (MANTRA; [11]), specialist supporting clinical management (SSCM), and family therapy. Compared with treatment as usual (TAU), psychological treatments are associated with modest improvements on clinical outcomes [12]. However, a meta-analysis reported no significant differences between psychological treatment (e.g. cognitive behavioural therapy, MANTRA) and control (e.g. TAU or SSCM) on weight gain, ED pathology, or quality of life [13].

Regarding pharmacological treatments, fluoxetine for BN and lisdexamfetamine for BED are the only approved medications for EDs [14]. There is no approved pharmacological intervention for AN, although individuals are frequently prescribed medication [15] to target comorbid disorders, such as depression [16] or anxiety, or to help with weight recovery [14]. However, the evidence remains inconsistent [14, 17]. The limited number of evidence-based medications for EDs is a severe limitation for their clinical management [18].

While some do recover with treatment, less than half will achieve recovery status (defined as weight restoration and no binge or compensatory behaviour for the prior 12 weeks) at long-term follow-up [19]. ED patients have expressed ambivalence around recovery, and dissatisfaction with treatment, pertaining to high levels of discontinuation and negative clinical outcomes [20] that are influenced by psychological, social, behavioural, and environmental factors at the individual and service level [21]. This underlines the urgent need for innovative and acceptable treatments and treatment escalation strategies. Building and implementing a treatment algorithm to escalate therapeutic intensity across ED staging, and incorporating psychedelics into later stages of this strategy, could help to create a progressive pathway of treatment for people who do not respond to first-line options [22].

Psychedelics are a subset of drugs that are characterised by their ability to induce altered states of consciousness, and produce profound acute effects on perception, cognition, and emotions [23]. The classification of psychedelics into classic and atypical is one driven by pharmacology [24]; to align with the literature that will be drawn on in this paper, we will refer to these substances under the broader umbrella of psychedelics. Classic psychedelics include psilocybin, lysergic acid diethylamide (LSD), and N, N-dimethyltryptamine (DMT). These compounds primarily act as agonists or partial agonists of the serotonin 5-hydroxtryptamine type 2a receptors. Classic psychedelics, specifically Ayahuasca (an Amazonian brew with the active ingredient DMT), have been traditionally used for decades in ritualistic and religious practices in Central and South America. Prior clinical studies investigating their effects and use were quickly prohibited due to increased recreational use, government regulations, and lapses in research ethics [25]. There has since been a resurgence in clinical interest of the therapeutic potential of psychedelics as novel treatments for psychiatric disorders, including EDs. As serotonin disturbances contributes to dysregulation of mood and appetite in EDs [26], classic psychedelics can enhance cognitive and neural flexibility [26, 27], and modulate mood, appetite, and perception [26]. Atypical psychedelics can be further divided into dissociative psychedelics (e.g. ketamine), cannabinoid agonists (e.g. Δ9 – tetrahydrocannabinol [Δ9-THC]), and entactogens (e.g. 3,4-methylenedioxymethamphetamine [MDMA]) [28]. Ketamine exerts effects primarily via N-methyl-D-aspartate receptor antagonism [29] and MDMA’s primary action is as a monoamine releaser [30]. MDMA promotes the release of oxytocin, which is implicated in social bonding and emotional regulation; this can encourage processing of unmanageable emotions, which is often central to EDs [26].

Psychedelics are partly characterised by their acute subjective effects and intense emotional states which are understood to be an important part of the therapeutic process [31]. These idiosyncratic effects occur in an altered state that is malleable and flexible [32], leading to personal insight by promoting cognitive flexibility, confronting challenging emotions, and enabling detachment from internal dialogue [27, 33]. The introspective quality of psychedelics may facilitate an embodied experience, enabling attunement with internal aspects of the self by increasing openness to new perspectives [26] and reconstituting a new-self model that improves identity and self-percept [34]. The benefits of using psychedelics for ED treatment are illustrated in several reviews pertaining to potential neurobiological and psychological mechanisms [23, 26, 27, 35], which are hypothesised to work symbiotically with “set” (expectation, psychopathology, and assumptions that the user has) and “setting” (the environment in which the psychedelic substance is taken) in shaping therapeutic outcomes [36]. There is positive preliminary clinical evidence for the benefits of psychedelics in ED populations [37–42] (Additional File 1: Table 1 [37–53]). However, there is a need for specifying protocols that mitigate risks associated with psychedelic use specific to those with EDs.

Challenges and needs unique to people with EDs include a heightened intolerance for uncertainty [54–56], difficulties with impulsive control and emotion regulation [57], substance abuse in binge-purge presentations of EDs [57, 58], and low body weight in AN. It is important to consider how these characteristics interact with risks and characteristics of psychedelics. Given the idiosyncratic acute effects of psychedelics and the complex heterogenous presentations of EDs, understanding the unique needs of the ED population is necessary to help to navigate potential challenges, maintain patient safety, and maximise the therapeutic potential of psychedelic treatments in those with EDs.

Whilst symptom overlap is observed, there are also features that differentiate EDs from other psychiatric conditions, necessitating a tailored approach rather than solely drawing on the experience and data of other psychiatric disorders. Psychedelics may offer therapeutic potential; however, their use introduces challenges that interact with the complex features of EDs, (e.g. physical vulnerabilities, uncertainty, and need for control) that need to be understood to minimise harm.

Qualitative research can improve understanding of phenomenological effects of psychedelics that are not accurately captured with quantitative measures [59], by generating valuable insight into acceptance, attitudes, subjective effectiveness, and how individuals experience psychedelic treatments. Such insights may highlight facilitators and barriers to their use, inform study design, and optimise clinical application and outcomes.

To our knowledge, there has been one previous review of qualitative data of psychedelics in EDs [60], which summarised perspectives on psychedelic therapies among people with a current or past diagnosis of ED, who did or did not have direct experience of psychedelics. A conceptual understanding of the experiential and contextual factors associated with psychedelic use in the ED population remains lacking. Using a meta-ethnographic approach, the present study aims to generate new, interpretative, higher order insights into the experiences of using psychedelics in ED treatment from the point of view of people receiving psychedelic treatment for EDs and providers that facilitate it. We aim to understand how acute psychedelic effects are experienced and how they contribute to therapeutic outcomes, and to understand ED-specific risks that should be considered in protocols for psychedelic treatment.

Qualitative studies exploring the experiences and perspectives of individuals with EDs and providers regarding psychedelic use in treating EDs were identified using electronic databases: PubMed, PsycINFO, and MEDLINE. Search terms pertained to psychedelics (e.g. psilocybin, ketamine, ayahuasca), EDs (e.g. AN, BN, BED, ARFID), and qualitative research (e.g. experience, perspective, qualitative). Additional papers were sought through manual searching on Google Scholar. The search was conducted in June 2025 without limits (see Additional File 1: Table). 2

Studies were included in the meta-synthesis if they: (1) reported qualitative data; (2) included the perspectives and experiences of providers (e.g., clinicians, ceremony leaders, etc.) and/ or individuals with current or past EDs; (3) were studies that explore the use of psychedelic drugs (e.g., psilocybin, ayahuasca, ketamine, MDMA, ibogaine, etc.). Studies could use any type of qualitative methodology and participants in studies did not have to have formal ED diagnoses.

Studies were excluded if they: (1) explored perspectives of other ED treatment options; (2) included individuals who were having psychedelic treatment for a psychiatric disorder other than an ED, or provided for individuals with a diagnosis other than an ED; (3) only used quantitative methodology; (4) did not include or define themes and quotes or; (5) were published in a language other than English.

The search results were screened by two independent reviewers (RM and AG) to identify included studies. The reasons for exclusion at full-text screening were recorded. Disagreements were resolved between the two reviewers (RM and AG) and if unresolved, were escalated to a senior reviewer (JK). This study selection process was documented in a PRISMA compliant flow chart; see Fig. 1.

The Critical Appraisal Skills Programme (CASP; [65]) checklist for qualitative studies was used by the two independent reviewers (RM and AG) to appraise included studies. Disagreements were resolved between the two reviewers. This study used an inclusive approach that did not exclude studies on the basis of CASP scores; scores are presented for context as an indication of the trustworthiness of the findings in the individual studies.

Both independent reviewers (RM and AG) extracted the following data: study characteristics (e.g. author, year, study design, country, data collection, and data analysis); sample characteristics (e.g. age, gender, diagnosis, and comorbid diagnoses); psychedelic (e.g. treatment setting/ environment, psychedelic drug, dose, and frequency); results (first order constructs [participant quotes], and second order constructs [themes, patterns and author descriptions/ interpretations]). Only findings relevant to the experiences and perspectives of psychedelic use as treatment for EDs were extracted for the synthesis. One reviewer (RM) cross-checked data extraction files for accuracy.

Both reviewers (RM and AG) independently familiarised themselves with each included study. The reviewers identified themes, concepts, and metaphors from each study. The headline, descriptor, exemplar method [62] was used, where the theme name, detailed description of the theme in the original authors words (second order constructs), and one verbatim “exemplar” of the theme from the perspective of the experiencing person (first order construct) was extracted.

The studies included two participant groups: individuals with EDs, and providers (e.g., clinicians, ceremony leaders, etc.). While these groups differed in perspective and background, the accounts often addressed overlapping concepts. Given the limited number of provider studies and the conceptual overlap between groups, all papers were synthesised together in a single interpretive process. However, there is also a distinction between epistemic knowledge produced by the individuals with EDs and providers. We have endeavoured to identify patterns that emerge across both individuals with EDs and provider perspectives, whilst also identifying and reflecting differences. Therefore, we have distinguished between the interpretations of individuals with EDs experiences and the interpretations of providers where relevant (e.g. spirituality sub-theme).

As concepts were largely comparable, reciprocal translation was performed. This involved an iterative process of translating concepts from one study into another by arranging the papers chronologically and comparing paper one with paper two, and so on until all papers had been synthesised. The translations were then synthesised to form new interpretive meta-themes and sub-themes (third order constructs). This was an iterative process until no new themes emerged. Senior reviewers (JK, HH, JT, VL) were consulted at this stage to offer additional insights and ensure clarity of the new themes, encompassing multiple perspectives here to reflect on bias. This discussion facilitated refinement of themes; one reviewer with lived experience of AN offered insights that informed revisions to meta-theme and sub-theme titles and merging or separating of themes. These refinements ensured that interpretations and the analysis were shaped by lived experience.

After developing meta-themes and sub-themes, an integrative narrative was constructed to illustrate how these themes relate to one another. This drew on the content of the themes and the researcher’s (RM) conceptual understanding and interpretations to develop a coherent account of how the meta-themes come together to collectively explain perspectives and experiences of psychedelics in EDs. This aligns with a line-of-argument synthesis, in that it aimed to explain how meta-themes fit together to form a broader, higher-order understanding of the phenomenon.

The first author (RM) then drafted the synthesis (results and discussion sections), which was refined after discussion with the other reviewers (AG, JK, HH, JT, VL).

This meta-ethnography is situated in an interpretivist paradigm, adopting a relativist ontology and constructivist epistemology. Here, multiple realities can co-exist. Knowledge is viewed as co-constructed through interaction of the synthesis researcher and the first- and second- order constructs of the original papers. We acknowledge that the researcher is inseparable from the research and acts as an active interpreter who produces a contextual interpretation of the data.

The process of the synthesis may be informed by collective personal and professional experiences of the researchers. The research team have reflected on their positionality related to the topic of this review, to identify and reflect on assumptions that may influence the review process. The authors identify as white female (RM, AG, JK, JT, VL) or male (HH) researchers in the ED field and are interested in psychedelics. Four senior reviewers (JK, HH, JT, VL) gave a broader perspective on the manuscript. JK is a translational researcher primarily in the field of ED research who also has past lived experience of AN. JT has 43 years of experience working as an academic psychiatrist at various levels of training, including consultant work for 35 years. VL is a qualitative methodologist whose research had sought to prioritise the lived experience of people with EDs. HH has 25 years of experience working as a medical doctor in psychiatry; of these 25 years, he worked 12 years in specialised ED services. HH has been the principal investigator (PI) of a proof-of-concept study testing psilocybin in people with AN and is currently the PI for a feasibility study of ketamine for AN and depression. RM, JK, VL and JT are also involved in the aforementioned feasibility study.

It is important for us to reflect on how these positions shaped the interpretive work presented. Considering the team’s involvement in psychedelic research, we acknowledge that expectations regarding the therapeutic potential of psychedelics are likely to have shaped the emphasis on “therapeutic improvements” as the endpoint of our interpretive narrative; however, this was also reflected in some of the primary studies where outcome-oriented findings were prominent. Further, our experience of developing protocols for a ketamine study in AN within a Western setting may have shaped the interpretations and narratives around ED-specific protocols, including aspects related to set and setting, and safety management within Western treatment settings, particularly for ketamine studies.

The search process yielded a total of 1205 studies through database searching, supplemented by 6 studies from additional searching on Google Scholar, resulting in a total of 1211 studies (n = 925 after deduplication). A total of 852 articles were excluded after title and abstract screening, one full-text article was not retrieved, and a further 64 articles were excluded at the full-text stage. Overall, eight studies met the inclusion criteria and underwent quality appraisal; see Fig. 1. The characteristics of the included studies are outlined in Tables 2 and 3.

Three studies investigated provider perspectives [66–68], whilst the remaining five explored the perspectives of individuals with EDs [69–73].

All five studies exploring individuals with EDs encompassed a range of EDs: two studies had a complete AN sample [69, 72], two consisted of AN and BN [70, 73], and the final encompassed AN, BN, BED, eating disorder not otherwise specified (EDNOS), and OSFED among others [71]. Three studies required diagnosis of ED by a qualified professional [70, 72, 73], one recruited individuals with current or past AN and associated body image disturbance (BID) [69], and the other recruited individuals both with and without professional diagnosis of an ED [71]. In two studies investigating ceremony leader perspectives [67, 68], nine of the 15 participants disclosed self-reported ED history, including AN, BN, or disordered eating.

Two studies recruited individuals with direct experience of being ayahuasca ceremony leaders, in which some of their participants had had EDs [67, 68]. In one study, topics explored included the utility of ayahuasca for EDs, perspectives on conventional ED treatment, and diet restriction and purging with ayahuasca in relation to EDs [68].The other asked questions pertaining to the utility of ayahuasca and its application for EDs [67]. The remaining study recruited individuals providing medical or psychotherapeutic care to patients with EDs, where three participants had completed psychedelic- or ketamine- assisted therapy training, but direct experience in providing this was not required [66]. In this study, clinicians were asked about their knowledge and attitudes towards using psilocybin in AN, education and training, and referring for psilocybin therapy [66].

Across all studies exploring people with lived ED experience, age ranged from 21 to 55, with sample size between six and 16, and majority female samples [69–73]. In the studies exploring provider perspectives, age of providers ranged from 30 to 60 (although two did not report range ([66, 68]), with sample size ranging between 15 and 32 ([66–68]. Gender was majority female in one [66] and more evenly split in the remaining two [67, 68].

Five studies looked solely at ayahuasca [67, 68, 70, 72, 73], two at psilocybin [66, 69], and one at any psychedelic [71]. Of the five studies exploring people with lived ED experience, three documented ayahuasca use in ceremonies and multi-day retreats [70, 72, 73]. One reported use in clinical trials, psychedelic rehabs, personal and social use, and in one case of ketamine, prescription for chronic pain [71]. The other did not report whether participants had prior psilocybin experience [69]. Regarding the number of uses, ayahuasca studies ranged from once to 30 times [70, 72, 73], one reported frequencies ranging from less than five times, to microdosing and lifetime recreational use [71], and one did not report [69].

Quality appraisal of the included studies utilised the CASP tool. Each paper was given a score out of ten representing high, medium, or low quality by the two reviewers (RM and AG). All eight papers were allocated a high-quality score of between 70 and 90% (Additional File 1: Table). 3

This meta-synthesis generated five meta-themes with a series of sub-themes (see Table 4; Fig. 2) that together depict how psychedelic experiences may act as catalysts for transformation. To provide an overview of how these meta-themes interrelate, the following narrative is proposed: core transformative processes (Mind-Body-Spirit, Emotional Processing), unfold within specific contextual conditions (Navigating Challenges and Risks, Enabling Safe and Supportive Experiences), and lead to meaningful outcomes (Therapeutic Improvements). The results are presented in the same structure as the above narrative, reflecting individual psychedelic experiences, factors related to set and setting, and broader subjective outcomes following psychedelic use.

Spirituality reflected a recognition of the purpose of life and the individual’s meaning in it, encompassing existential understanding and self-reflection. For some, this realisation provides a pathway to reconnecting with the self and appreciation of the body. This aligns with psychedelics promoting connection to the world and encouraging a transformed outlook on one’s life [59]. In contrast to the phenomenological descriptive accounts of individuals with EDs, providers offered interpretive insights into theoretical aetiological about EDs. Ayahuasca ceremony leaders highlighted the importance of spirituality in ED onset and development, which aligns with recognition of EDs and mental health as inseparable from physical, emotional, and spiritual aspects of the being in Indigenous cultures [74]. This contrasts with biomedical approaches which tend to prioritise empirical evidence about ED aetiology.

Emotional dysregulation is a transdiagnostic factor of EDs, where individuals have difficulty in accepting, experiencing, and attending to emotions [75–77]. Emotional Processing and Discovering Root Causes refers to the process where insights and knowledge otherwise inaccessible or supressed, are revealed and evoke meaning for the user experiencing them. These themes align with psychedelic research in a mixed sample of EDs, felt that psilocybin enabled processing of these emotions [59]. Here, confrontation and acceptance of emotions appeared to be linked with reuniting and reconnecting with the self. Individuals with EDs often experience their disorder as a part of their identity where the ED is integral to the self-concept; thus, reconstructing identity and valuing the authentic self as recognised central features of recovery [78–82]. Shifts in personal identity and reconstructing the self are features documented in other psychedelic research within ED samples, reflecting an improved sense of connection to self-hood and moving away from the ED as a central part of identity [48, 59]. As the physical entity and representation of the self, body image disturbance in EDs is often resultant from a difficulty in building the self and experiencing inner states and identity [83]. Newfound perception of the body encompassed a reconfiguration and reconnection with the physical form of the self, where individuals reframed the body as a valued entity that needed nourishment. This aligns with other qualitative work in ED samples, where psychedelics promoted improved relationships with the body, improved perception and acceptance of the body, and reduced the importance of the physical appearance, decentralising weight and shape [48, 59].

While definitive mechanisms of action cannot be identified from this meta-synthesis, the interpretation presented in our results suggests that reuniting and reconnecting with the self, newfound perception of the body, and emotional processing may function as psychological processes through which psychedelics exert, or contribute to, therapeutic effects including ED-specific changes, improved psychological wellbeing, and changes in social domains; this hypothesis should be investigated empirically, in larger samples to better capture both homogeneous and heterogeneous experiences across ED diagnoses. Prior research highlighted that improvements in emotion regulation had an indirect effect on improvement in ED psychopathology symptoms through improvements in self-image, highlighting emotion regulation and renewed body perception as mechanisms of change for ED outcomes [84]. Furthermore, increases in self and identity coherence were associated with a decrease in drive for thinness and body dissatisfaction [85]. Recognising these processes and potential mechanisms can guide clinicians in shaping preparation and integration sessions to support shifts in self-concept, body perception, and identity, and to facilitate emotional exploration and processing.

The potential of the core transformative processes contributing to therapeutic improvements discussed here is dependent on the containment of the psychedelic experience within a suitable and safe set and setting (also referred to under the umbrella “context”) [36, 86].

The themes discussed in this meta-synthesis broadly align with the set and setting framework. Sub-themes relating to internal psychological factors, such as unpredictability, expectations, and ED thoughts and behaviours map on to set. Several factors, such as unpredictability and trust, intersect both set and setting domains. This section explores these sub-themes and the set setting framework in more detail.

The role of the facilitator within psychedelic treatment and the psychotherapeutic intervention they deliver is immersed within the set and setting, thus, they co-define set and setting within psychedelic sessions [87]. As demonstrated in our sub-theme, Trust in facilitator and provider, therapeutic alliance is important for ensuring safety and enhancing treatment outcomes, with research reporting a reciprocal relationship between symptom change and therapeutic alliance [88]. Moreover, trust in the provider of treatment is pertinent to recovery in EDs [89] and is seen as an important characteristic of facilitators of psychedelic sessions [90]. More broadly, the trust in the provider, partly shaped by confidence in their ethical conduct and the supervised training they receive in accordance with specialist guidelines, may also contribute to ensuring safety and mitigating risk to harm. This holds paramount importance within the psychedelic space given recent cases of abuse of patients by therapists during psychedelic therapy [91], and rates of individuals being or knowing a victim of inappropriate sexual contact by a guide, sitter, or practitioner during a psychedelic experience [92]. These accounts of boundary violations are fundamentally rooted in the abuse of power held by the facilitator [93]. It is important to highlight the complex power dynamics between the client and facilitator, which is typically imbalanced, and differs markedly between medical clinical and ceremonial use. In traditional ceremonial contexts, ceremony leaders hold considerable authority that is spiritual, physical, and experiential. Power is firstly derived from a spiritual authority wherein the community perceives their connection to plant spirits and sacred knowledge, and their ability to mediate between human and spiritual realms. Experiential authority is derived from the personal knowledge of altered states and the ritual experience. Contrastingly, in clinics, authority and power comes from professional qualifications, ethical guidelines, and protocols. Here, therapists facilitate the psychedelic experience rather than direct and participate in it.

Facilitators of psychedelic treatment require dual competency: first in elements specific to the type and context of psychedelic intervention being delivered, including medical administration (e.g. intravenous ketamine), dosing monitoring and facilitation, preparation and integration, and traditional ceremonial practice (e.g. ayahuasca), and secondly, in ED-specific psychopathology. Development of ED-specific training manuals and ethical frameworks that guide specific psychedelic processes from beginning to end (e.g. preparation, integration, therapeutic frameworks, therapeutic touch, rescue medication, additional ongoing support, medical chaperone) is necessary and should be prioritised with future research for clinical implementation.

A first consideration is screening protocols that assess risk, specifically substance-specific challenges and ED-specific contraindications. Ritualistic components of Ayahuasca may further trigger ED symptoms (e.g. restriction and purging) or be particularly challenging for these individuals. In our results, for most individuals, this was experienced in a different way to an ED context, but for some, this may present an opportunity to engage with or reinforce ED behaviours. Likewise, the side effect of nausea that is reported by approximately 8–15% [94, 95] of participants receiving therapeutic ketamine, may contribute to loss of appetite during the dosing period.

Other criteria may include body weight. Low body weight is a physical vulnerability specific to AN, where a dangerously low body weight could increase the risk of adverse side effects of psychedelics [35]. This concern is more pertinent for atypical psychedelic use, as classic psychedelics are not typically weight-dosed; low body weight could translate to intense acute effects in atypical psychedelics like MDMA [35], and ketamine overdose may result in death [96]. However, there is evidence of preliminary safety for adequately-dosed ketamine in AN patients with low weight and medical instability [42]. Other physical medical complications in EDs include structural and functional cardiac abnormalities, including heart rate and rhythm [97] and in EDs with purging presentations, electrolyte abnormalities [98]. These medical risks can exacerbate the potential for adverse effects with psychedelic use and require consistent and ongoing monitoring throughout treatment [99], including at dosing, such as electrocardiograms [97]. Given the heterogeneity within individuals with EDs [100], a personalised approach should be adopted. Treatment may begin with low doses and titrate according to clinical response, measured through ongoing physiological and psychological monitoring, and preference of the individual.

Additionally, dependency may be included in screening criteria. People with binge-purge type EDs (e.g., BN, BED) often experience difficulties with impulsive control and emotion regulation [57]. Research has demonstrated higher prevalence of substance use in binge-purge presentations of EDs [57, 58]. Models of EDs suggest that individuals may rely on ED behaviours as a coping mechanism for underlying unmanageable emotions [4]. Few hallucinogen users experience dependence [101] and psychedelics are considered low risk for dependence [102]; however, there has been concern for the addictive properties of ketamine since mu-opioid receptors may be in part necessary for the therapeutic antidepressive effects of ketamine [103]. These receptors are linked to reward and reinforcement processes that are implicated in dependence, although a review of 16 studies reported tolerance or dependence in only four of 2174 participants (~ 0.2%) [104] and recreational abuse doses are substantially higher than those administered in clinical settings [105].

Developing ED-specific screening criteria to ascertain which psychedelic may be most suitable for which ED diagnosis, consideration to optimal dosing, and at what stage of ED this treatment may be most effective, would mitigate possible exacerbation of symptoms and improve therapeutic outcomes.

In light of the potential risks of using psychedelics in the ED population, it is notable that what constitutes “safe” practice in Western clinical and medical protocols may vary from the Indigenous traditions and practices [106]. In an analysis of psychedelic retreat organisations, McGuire et al. [106] documented variability in safety practices such as screening, medication management, and integration services provided. Some organisations reported that facilitators consumed psychedelics alongside participants, which, whilst typical of Indigenous tradition, could compromise capacity to respond to emergencies [106]. These cultural differences that influence what is considered as “safe” practice align with the environmental and cultural aspects of setting.

As explored in our results, it is important to manage patient expectations of outcomes and experiences, and balance expectations with reality. In preparation sessions, exploring one’s intentions and expectations of using psychedelics, discussing potential risks and benefits of this treatment, and devising strategies for responding to difficult experiences, may increase the likelihood of a potentially therapeutic experience [107]. During the acute experience, there is a possibility for “bad trips” which are characterised by overwhelming feelings of distress and confusion [108]. Several factors contribute to the risk of a “bad trip”, which are often encompassed within set and setting. There are high levels of emotional avoidance in individuals with EDs, where being confronted with the challenging emotions that they are trying to avoid may contribute to a difficult experience or a “bad trip”. Predicting individuals who may be more susceptible to experiencing a “bad trip” is critical for tailoring interventions and making adaptations to ensure safety [108]. Further, there are ethical challenges that exist simultaneously with “bad trips”, including the availability of long-term support and the possibility of re-traumatisation [108]. This is paramount given the ideology that EDs are coping mechanisms for prior interpersonal trauma and the rates of high traumatic experiences in individuals with EDs [5]. Moreover, “bad trips” can exacerbate pre-existing, or induce new, symptoms or disorders [109, 110], or can be harnessed for therapeutic benefit [108]. Unpredictability as a central risk of psychedelic treatment reflects how drive for control and high rates of anxiety typify EDs, mapping on to the set domain. Given the unpredictability of the acute psychedelic experience, and heightened intolerance for uncertainty in EDs [54–56], being able to prepare for and manage unpredictability, to prevent “bad trips”, is pertinent to the ED population. Further, treatment that takes place in medical environments may intersect with iatrogenic harm experienced by individuals with EDs who have had repeated admissions [111]. Giving the individual input over setting features (e.g. whether the room has a chair or a bed, lighting adjustments, volume and type of music) may promote autonomy and reduce uncertainty. These are subjective features of setting that should be adapted accordingly to patient preferences, and this customisation should be documented [112]. The provider and individual should collaboratively agree on mitigation strategies for if, and when, anxiety arises during the acute experience (e.g. consensual therapeutic touch). Further, explaining an approximate timeline and structure of the overall treatment model and of each visit may provide some anxiety relief.

Integration sessions provide a unique opportunity for psychedelic experiences to be explored, processed, and linked to the individuals ED. The therapeutic framework of integration sessions in psychedelic clinical trials has varied between studies. Provided there is synergy between the therapeutic intervention and the psychedelic to promote desired outcomes, various forms of intervention could be adapted for use in psychedelic treatment [113]. The Yale manual for psilocybin-assisted therapy of depression [114] is based on the therapeutic framework of acceptance and commitment therapy (ACT), which has reasonable efficacy for improving ED symptoms [115]. Indeed, there is opportunity for integrated care models that bridge psychedelic treatment with conventional ED treatment frameworks or modules. Our results encompassed how psychedelics and conventional ED treatments could be integrated to maintain long-term positive therapeutic outcomes, by leveraging the strengths of different treatment types. This is already seen within MDMA research, which has thus far been explored mainly for post-traumatic stress disorder (PTSD), whereby there is an addition of structured trauma-focussed psychotherapy interventions with trained psychotherapists [116]. A similar vein should be followed for treatment of EDs, integrating modules from conventional models such as MANTRA and CBT-ED, with specifically trained providers.

When considering ED-specific protocols for the use of psychedelics in treatment, attention should be paid to their traditional uses. Clinic-based psychedelic use typically takes place in controlled environments with one or two therapists present to provide reassurance; contrastingly, traditional ceremonial psychedelic use takes place in naturalistic outdoor settings, typically done within a group with emphasis placed on community and social contexts. The collective rituals in psychedelic ceremonies produce shared awareness, connectedness to others, and empowerment of the individual through the collective [117]. Implementing these collective aspects of Indigenous psychedelic ceremonies may bring about challenges for individuals with EDs who experience social anxiety [6], such as increasing the risk of the individual having a “bad trip”. However, group-based ketamine yielded positive preliminary results in a case series of five individuals with an ED [118]. Psychedelic ED-specific protocols may be informed by Indigenous knowledge whilst accounting for the individual and providing tailored, person-centred care where possible.

In addition to differences between clinical and ceremonial settings, the underlying approaches to EDs also diverge. Indigenous approaches to EDs are fundamentally holistic, placing emphasis on relational connections and spirituality [74]. While Western models generally include social, relational, and cultural aetiological aspects of EDs, and consider some environmental influences (e.g. media influence, food insecurity), a key distinction is that Indigenous approaches extend this relational lens to include ancestry, nature, land, and spiritual connections; these are contexts that traditional psychedelic practices are grounded in.

The recent resurgence of psychedelics in White-dominant Western cultures has inadequately recognised the cultures in which they originate, raising concerns regarding cultural appropriation of medicines and exclusion from research endeavours [119, 120]. Western research has thus far approached psychedelics through a clinical biomedical lens that generally ignores the traditional Indigenous knowledge that these substances are sacred, relative and spiritual beings [121]. The continual underinvolvement of Indigenous people and knowledge in Western research contributes to patterns of oppression and marginalisation seen throughout colonial history; this is furthered by ethical concerns of cultural erasure and biopiracy that fails to gain permission or fairly compensate Indigenous communities who developed and preserved this knowledge [121]. As the Western psychedelic research field moves forward, attention should be paid to developing a non-extractive process of exchanging of knowledge emphasising the necessity of ethical relationships that receive mutual benefit and provide equal opportunity for Indigenous people to be involved in co-developing and co-leading research. These efforts should be in addition to addressing and repairing historical and ongoing harms caused by previous extraction [121].

The sample of participants in the included studies were relatively homogenous regarding gender and ED diagnoses, with majority of female AN individuals represented. It is important to understand the experiences and perspectives of the use of psychedelics in other genders, and other EDs, such as ARFID and BED. Similarly, most included papers investigated ayahuasca or psilocybin. Only one included paper [71] pertained to other psychedelics, such as LSD or ketamine. There were no qualitative studies exploring solely ketamine in EDs, despite the array of case studies and series in the literature. Due to the small number of studies and participants, deducing substance-specific experiences and perspectives for the treatment of specific ED diagnoses was not possible. Further, factors related to psychedelic use, such as setting and frequency were heterogeneous across studies. These elements may hold influence over how psychedelics are experienced and perceived as potential treatment options for EDs.

Whilst there was considerable variability in key features of the primary studies, all studies were the same in their methodological biases. Participants were self-selected, resulting in a sample that is likely not representative of the spectrum of experiences of psychedelics in the ED population, as those who experienced adverse outcomes are less likely to volunteer to take part in the primary studies. Participant selection of primary studies would also be limited to individuals with EDs who both wanted to participate and had access to psychedelic treatment. Additionally, as all eight studies were conducted in Western cultures; the findings likely fail to generalise to other cultures, where cultural background shapes interpretation and meaning-making of experiences. Qualitative findings pertaining to ayahuasca may be framed through the Western biomedical lens, whereby in turn, this synthesis is approached through the same lens. The inclusion of an Indigenous person in this meta-synthesis may have resulted in a different interpretation of the studies investigating ayahuasca, which poses a limitation to the interpretative narrative presented.

Quantitative psychometric measures that aim to capture either the psychedelic experience or ED psychopathology (e.g. EDE-Q) are rooted in pre-existing frameworks that may miss meaningful variations in idiosyncratic experiences [78, 122] and fail to capture dimensions relevant to individuals with EDs [78]. It is therefore essential that future research collects detailed qualitative data about the experience of psychedelic treatment from individuals with EDs. Questions such as which psychedelics at what doses and frequency are most suitable for which ED diagnosis, and at what stage of illness these are best used, with what level of support, remain unanswered. Here qualitative enquiry can highlight individual factors that may shape these decisions, including what feels tolerable, interpretations and meaning-making of the acute experience, and what forms of support are needed. Quantitative means, such as dose ranges, physiological responses, and therapeutic drug monitoring, would provide complementary objective information. These lines of enquiry will be essential for eventually developing ED-specific psychedelic manuals and training.

Currently, there is a lack of Indigenous input in Western psychedelic research [119]. The traditional rituals, methodologies, and approaches of psychedelics in Indigenous cultures may enrich Western psychedelic frameworks by becoming embedded in the community and spiritual practice, instead of isolating compounds and viewing them as merely chemical [121]. We recommend that ED-specific psychedelic manuals and protocols for psychedelics adopted from Indigenous cultures, such as ayahuasca, are co-designed with people with lived ED or psychedelic experience and people from Indigenous cultures. These collaborations may also be relevant to optimising the experiences of Western substances, such as ketamine. This work will help to ensure the future use of psychedelics is safe, meaningful, and relevant for the ED population.

The acute non-ordinary states induced by psychedelics are often described as ineffable or indescribable, where language is inadequate to convey experiences; despite this quality, attempts to describe these experiences appear to be for therapeutic benefit and can be meaningful [123]. Future research should make efforts to analyse content and linguistic choices made in describing these experiences [124] with hope to derive meaningful patterns in language and thus, deeper insights. Alternatively, where words still feel insufficient to some, the use of art therapies (e.g. painting) may provide a creative outlet to convey experiences. Arts-based therapies in EDs are reported to support new perspectives, expression, and awareness [125], with significantly better functioning than individuals not receiving art therapy [126]. Arts-based therapies could serve as tasks for integration in psychedelics, by facilitating processing and exploration of the acute experiences.

This meta-synthesis explored experiences of psychedelics in ED treatment, focusing on perspectives of providers and individuals with EDs. By integrating findings across the eight included qualitative studies, we build a broader understanding of how psychedelics may be used for ED treatment, founded on the experiences and perspectives of those with lived experience. These findings suggest that to achieve subjective positive therapeutic outcomes, ED-specific contextual conditions (e.g. management of contraindications and uncertainty, integrating psychedelics with current ED treatments, and implementing screening protocols) may be necessary to facilitate internal transformative processes. Further, collaborative qualitative research of individuals with EDs undergoing psychedelic treatment may be conducted to better understand the phenomenology of the acute experience, and how features perceived as central to psychedelic therapy may be adapted for the ED population.

Not applicable.

HH, JLK, and JT report funding from the UK Medical Research Centre (MRC) for a double-blinded randomised controlled trial to test oral ketamine in people with anorexia nervosa and depression (MR/Y019504/1). HH was the principal investigator of a phase 2 clinical trial investigating the efficacy and safety of investigational COMP360 psilocybin treatment in anorexia nervosa.

Not applicable.

No datasets were generated or analysed during the current study.