Co-use of MDMA with psilocybin/LSD may buffer against challenging experiences and enhance positive experiences

Classic psychedelics such as psilocybin and LSD produce experiences that can range from profoundly positive to highly challenging (for example, fear, grief and paranoia). These challenging experiences are reported in both clinical and non-clinical contexts and are a common source of reluctance among clinicians and potential patients for psychedelic-assisted therapies. Anecdotal reports and recreational practices describe co-use of MDMA with psilocybin or LSD (commonly called “hippy flipping” or “candy flipping”) as a way to reduce challenging experiences and enhance positive effects, but empirical data on the acute effects of such co-use are limited. A recent controlled study examined LSD plus a medium-high MDMA dose and found no acute differences, but that trial used a restricted, screened sample, a single MDMA dose, and did not assess some positive-affect outcomes that MDMA might influence. L. and colleagues therefore set out to examine, in a prospective convenience sample of people planning to use psilocybin or LSD in naturalistic settings, whether self-reported co-use of MDMA (categorised as none, low, or medium–high dose) was associated with differences in acute challenging experiences (measured by the Challenging Experience Questionnaire) and positive experiences (measured by the Mystical Experience Questionnaire and single-item ratings of self-compassion, compassion, love and gratitude). The study aimed to account for plausible confounds and to provide exploratory evidence about whether co-use buffers against adversity or enhances positive affect during psychedelic experiences.

Design and recruitment. The researchers combined data from two near-identical online prospective surveys recruiting individuals who planned to use a psychedelic in a naturalistic setting. Both studies were approved by Imperial College London research ethics bodies. Eligibility criteria were age 18+, English literacy, and intention to use a psychedelic. Participants were recruited via online adverts, social media and forums. Surveys were administered seven days before the planned experience and one day after the experience. Only participants who used either psilocybin or LSD alone, or psilocybin/LSD together with MDMA, were included; participants who used other additional substances during the experience were excluded. Measures. Pre-experience data included demographics, personality (Ten Item Personality Measure; TIPI), psychiatric history and lifetime psychedelic use. Post-experience measures (collected the day after use) included the Challenging Experience Questionnaire (CEQ; total score and seven subscales: grief, fear, physical distress, insanity, isolation, death, paranoia), the Mystical Experience Questionnaire (MEQ-30; total and four subscales), and single-item visual-analogue ratings (0–100) of self-compassion, compassion for others, gratitude and love. Participants reported the psychedelic used and its dose (categorised into ordered dose bands for LSD/psilocybin) and whether they co-used MDMA (none, low, medium, high); because only one person reported high MDMA, medium and high were collapsed into a single medium–high category. Participants also reported contextual factors (setting, music, live singing, emotional support, threat, strangers, disruption). Statistical approach. Dependent variables were non-normally distributed, so preliminary Kruskal–Wallis tests (no covariates) were followed by Dunn post-hoc tests when main effects were significant. Potential confounders were identified by testing whether baseline/demographic/contextual variables differed across MDMA dose groups (p < 0.05); variables significantly associated with MDMA use were included as covariates. Multicollinearity among covariates was checked via Pearson correlations and variance inflation factors. Primary adjusted analyses used Quade nonparametric ANCOVAs with MDMA dose (none, low, medium–high) as the independent variable, controlling for selected covariates. The analysis plan examined CEQ total and subscales, MEQ-30 total and subscales, and the positive single-item measures. All analyses were conducted in SPSS with two-tailed p < 0.05 as the significance threshold.

Sample and grouping. The final sample comprised 698 participants. Of these, 342 reported using LSD and 356 reported using psilocybin during the indexed experience. Twenty-seven participants reported co-using MDMA with psilocybin/LSD (14 psilocybin + MDMA; 13 LSD + MDMA). Because only one individual reported high-dose MDMA, the researchers combined medium and high categories into a medium–high group, producing three MDMA groups: none, low, and medium–high. Covariates. MDMA use category was significantly associated with several baseline/contextual variables: conscientiousness (lower in low-dose co-users), openness (lower in medium–high co-users), and contexts of use including recreational/social setting, live singing, emotional support and presence of strangers (variously higher among co-users). Correlations and VIFs indicated multicollinearity was not a concern, so these variables were included as covariates in adjusted analyses. Challenging experiences. In adjusted analyses there was a significant overall group effect for total challenging experience (CEQ Total; F(2,672) = 3.62, p = 0.031). Post-hoc comparisons showed that psilocybin/LSD + low-dose MDMA was associated with significantly lower total challenging experience than psilocybin/LSD alone (t(672) = 2.54, p = 0.011). Psilocybin/LSD + medium–high dose MDMA did not differ significantly from psilocybin/LSD alone (t(672) = -0.68, p = 0.498). On CEQ subscales, co-use was associated with significant group differences in grief and fear (reductions evident for the low-dose MDMA co-use group). Although death-related items were descriptively lower in the low-dose co-use group, when controlling for covariates co-use was not associated with significant differences across other CEQ subscales (physical distress, insanity, isolation, paranoia). Positive experiences and mystical-type experience. Co-use of MDMA with psilocybin/LSD was associated with higher self-reported self-compassion, feelings of love and gratitude (F(2,256) = 3.62, p = 0.028; F(2,256) = 3.97, p = 0.020; F(2,256) = 3.92, p = 0.021, respectively). Post-hoc tests indicated that these increases were driven by the low-dose MDMA co-use group relative to psilocybin/LSD alone (self-compassion: t(256) = -2.61, p = 0.010; love: t(256) = -2.69, p = 0.008; gratitude: t(256) = -2.12, p = 0.035). The medium–high MDMA co-use group did not differ significantly from psilocybin/LSD alone on these measures. Co-use was not associated with significant differences in single-item compassion (F(2,256) = 2.67, p = 0.071) or overall mystical-type experience (MEQ-30 total or subscales), although some MEQ subscales showed divergent descriptive patterns across groups.

The authors interpret the findings to indicate that, in this convenience prospective sample, co-use of low-dose MDMA with psilocybin or LSD was associated with reduced overall challenging experiences and specifically lower grief and fear, alongside increases in certain positive affective states (self-compassion, love and gratitude). These effects are consistent with MDMA's reported pharmacological and subjective profile (reducing fear and sadness and increasing affiliative/positive emotions) and with anecdotal reports that people co-use MDMA to buffer challenging psychedelic experiences. The authors note that co-use did not significantly affect several other CEQ domains (physical distress, insanity, isolation, paranoia) or MEQ-30-measured mystical-type experiences, suggesting a possibly selective effect on affective components rather than cognitive or existential components of challenging experiences. They highlight a dose-dependent pattern in which low-dose MDMA co-use showed associations while medium–high dose did not; this mirrors some prior observations with other co-used drugs (for example, cannabis) and aligns with a recent controlled study that similarly found no acute differences when a medium-high MDMA dose was paired with LSD. The authors caution that non-significant results for medium–high doses do not prove absence of effect and that small sample sizes reduce power. Key limitations acknowledged by the authors include the non-experimental, uncontrolled design; convenience sampling with a largely psychedelic-experienced and demographically limited cohort; small number of MDMA co-users (especially for medium–high doses); use of single-item, non-validated measures for several positive outcomes; lack of precise timing and pharmacological dosing information; and the exploratory analysis plan that did not correct for multiple comparisons. Because of these limitations the authors emphasise that the findings are preliminary and hypothesis-generating rather than confirmatory. Implications and future directions discussed by the authors include the possibility that, if confirmed by pharmacokinetic and controlled dose–response studies, MDMA co-administration could be explored to mitigate challenging experiences in clinical contexts or to enhance particular positive-affect outcomes (for example, in couples therapy or gratitude-focused interventions). They also note an important unresolved question: some researchers and clinicians consider challenging experiences to be integral to therapeutic benefit, so co-administration could in theory attenuate therapeutic mechanisms. The authors call for larger, controlled, dose–response and clinical-sample studies using validated instruments to clarify safety, efficacy, timing, and which patient profiles (if any) might benefit from co-administration strategies.