Various studies into psychedelics in 2025

Below, I have compiled a list of studies and research into the efficacy of psychedelics. Each entry briefly mentions the study design and the key findings.

Randomized and open-label clinical trials

• Psilocybin and alcohol addiction – In an RCT with 84 patients with alcohol use disorder, researchers compared psilocybin therapy with an active placebo. Psilocybin led to marked decreases in neuroticism and impulsivity and to an increase in extraversion and openness. The decrease in impulsivity was associated with lower alcohol use after treatment.
• Psilocybin for stubborn depression – An open-label trial administered a single dose of 25 mg psilocybin to twelve people with severe, treatment-resistant depression. Depression scores (MADRS) decreased significantly at week 3 and week 12. The degree of oceanic boundlessness during the session correlated with the antidepressant response.
• Natural or “field” study with psilocybin – A cohort that received a high dose of psilocybin with psychotherapy reported less anxiety and depression and more openness and conscientiousness three months later. Mystical experiences, emotional breakthroughs, and meaningful personal growth appeared to reinforce the positive changes.
• DMT/harmine formulation – A double-blind, placebo-controlled study in 31 men tested an innovative formulation with N,N-dimethyltryptamine (DMT) and harmine. DMT reached peak concentrations of approximately 22 ng/mL and caused short-lived ayahuasca-like effects; harmine reached 32.5 ng/mL without noticeable subjective effects. The combination was safe and well tolerated.
• Ketamine versus midazolam in depression – In a multisite trial, a cohort received subcutaneous ketamine (0.5 mg/kg) or midazolam. At a fixed dose, ketamine did not significantly reduce anxiety, but in a flexible dosing strategy, the reduction in anxiety according to the Hamilton Anxiety Scale (HAM-A) was greater than with midazolam. The effect did not persist four weeks after completion.
• Repeated esketamine infusions – In 18 patients with treatment-resistant depression, repeated intravenous esketamine infusions improved not only mood but also the perception of emotions. The bias toward recognizing sad faces decreased and cognitive performance improved.
• Ketamine versus midazolam in adolescent girls – In a randomized study with 55 adolescents (all girls) with TRD, both ketamine and midazolam reduced depressive and anxious symptoms; ketamine led to more responders (33 % vs. 14 % after 2 hours) and reduced inner tension more strongly.
• Maintenance treatment with intranasal racemic ketamine – A small-scale observational study followed five patients who used intranasal ketamine for approximately six months. Depression scores remained low or decreased, and quality of life improved. Side effects were mild (including nausea and a slight increase in blood pressure); no serious side effects occurred.
• Proteomics and ketamine response – In 30 patients with major depressive disorder, researchers identified six proteins associated with the antidepressant response to ketamine. The changes indicate the involvement of immune processes; some protein levels before treatment could predict responding patients.
• EEG correlates of ketamine induction – A study in 30 people with bipolar depression showed that subanesthetic ketamine lowered low EEG frequencies, increased gamma oscillations, and increased the entropy of brain signals. These changes were stronger in patients who later responded better to treatment.
• Real-world study of esketamine – A retrospective Italian study followed 63 patients who received esketamine nasal spray; 76% of % were responders or remitters after six months. Side effects such as sedation and dissociation were frequent at the beginning but decreased; only two patients discontinued due to tolerance problems.

Other clinical trials and interventions

These are the smaller trials and interventions briefly summarized here:

• Ketamine in Rett syndrome – A crossover study tested ketamine in 21 women with Rett syndrome. The treatment proved safe but did not improve daily activity or well-being.
• Ketamine as an aid in quitting smoking – A pilot study investigated ketamine (0.5 mg/kg intravenously) in smokers but found no significant difference compared to placebo in quitting smoking.
• Ayahuasca retreat – Participants in a multi-day ayahuasca ceremony reported afterwards an increase in positive mood, mindfulness, and psychosocial functioning, and a decrease in problematic alcohol use. Deleted link
• Virtual reality with illusory hallucinations – A proof-of-concept in which virtual psychedelic images were shown led to a temporary increase in cognitive flexibility and divergent thinking.
• REBAS (REBUS versus REBAS) – A double-blind study compared psilocybin (25 mg) among two therapeutic approaches for depression. Both groups reported lower negative self-beliefs and suicidality; the pre-dosing sessions had a major influence on the outcome.
• Magnesium and impulsivity – A study found no association between magnesium status and impulsivity in people receiving psilocybin-assisted therapy.

Case studies and case series

These are the studies and also contain various case descriptions:

• Ketamine-assisted psychotherapy for antisocial personality disorder – A patient who received multiple ketamine sessions showed relief of aggression and improvement in social functioning.
• “Psilocybin experience went wrong” – This case described a person with underlying psychosis who experienced a prolonged psychotic episode following recreational psilocybin use.
• Low-dose MDMA for neuropathic pain – In one case, repeated low MDMA dosing led to a significant reduction in chronic neuropathic pain.
• Cardiac arrest after ketamine – A case series reported a rare cardiopulmonary arrest shortly after a ketamine infusion; the patient survived but illustrated the importance of medical supervision.
• Suicide after psilocybin therapy – One case was described of a patient with chronic suicidality who committed suicide after psilocybin therapy; the authors emphasized the importance of screening and aftercare.

Observations and surveys

Multiple studies mapped patterns of psychedelic use and behavior:

• Importance of community in psychedelic therapy – Interviews with participants in community-oriented sessions emphasized that support after the experience (community-building) is crucial for integration and well-being.
• Hallucinogens and mental health – Large surveys found that individuals who used hallucinogens reported more underlying mental disorders, which may indicate self-medication or selection.
• Fear of death and psychedelics – A survey showed that people who have used psychedelics report less fear of death and more acceptance of death, especially if the experience had a mystical quality.
• Ketamine use and risks – Surveys indicated rising non-medical ketamine consumption, with a risk of bladder and liver problems. Illegally obtained ketamine sometimes contained impurities.
• Online self-reports – Analysis of Reddit posts about psychedelics in opioid use suggested that some users use psilocybin or LSD during withdrawal, although systematic data are lacking.
• Personal values and usage – A Finnish survey showed that users of psychedelics often had higher scores on values such as connection to nature, self-transcendence, and openness.

Meta-analyses and systematic reviews

• Psilocybin for depression – A network meta-analysis of randomized trials concluded that psilocybin (10–25 mg) was more strongly associated with remission of major depression than placebo or usual care, but highlighted the small number of studies and the lack of long-term data.
• Acute cognitive effects – A meta-analysis found that psilocybin slightly impairs attention and executive functions in the short term, but that this effect disappears after a few days.
• Esketamine spray meta-analysis – A review of nine RCTs showed that intranasal esketamine combined with an antidepressant leads to faster response and remission than placebo, but also to more dissociation and an increase in blood pressure.

Review articles and commentaries

The list of studies contains dozens of review and opinion articles. Some themes:

• Psychedelics as antidepressants – Reviews emphasize that psilocybin and ketamine have fast-acting antidepressant effects, possibly via neuroplasticity, anti-inflammatory effects, and serotonergic modulation.
• Chronic pain – Reviews suggest that psychedelics may provide relief for some forms of chronic pain (migraine, cluster headache), but clinical evidence is scarce.
• Safety frameworks – Commentaries call for robust ethical guidelines to prevent abuse and transgressive behavior in psychedelic therapy
• Pharmacokinetics and interactions – Various reviews discuss the metabolism of DMT, psilocybin, and ketamine, and the possible interactions with SSRIs and other medications.
• Psychedelic exceptionalism – Some authors warn against glorifying psychedelics as miracle cures (“exceptionalism”); others, on the contrary, advocate recognition of their unique mechanisms of action and the need for specific regulation.

Preclinical research

Numerous animal studies in 2025 investigated mechanisms of ketamine, psilocybin, and other entactogens:

• Mouse models showed that esketamine inhibits inflammation and provides neuroprotection in adolescents via the Nrf2 signaling pathway
• R- versus S-ketamine – In pain models, the enantiomers were found to have different effects on hyperalgesia
• Psilocybin and microstructure – Rats repeatedly given psilocybin showed an increase in synaptic plasticity and changes in brain connectivity.
• Addiction models – Research into LSD/MDMA combinations and ibogaine analogues indicated potential addiction-relieving effects.

Theses and health economic analyses

Several Master's and PhD projects focused on:

• Education on ketamine-assisted psychotherapy (KAP) – An intervention program for therapists and clients was evaluated for knowledge gain.
• Group versus individual KAP – A pilot study compared both approaches in terms of effectiveness and costs.
• Cost-effectiveness of esketamine versus electroconvulsive therapy (ECT) – An economic model suggested that esketamine is more expensive than ECT in the long run but remains attractive to patients due to its less invasive nature.

Conclusion

The 2025 overview shows an explosion of research into psychedelic therapies. Randomized trials confirm the rapid antidepressant effect of psilocybin and (es)ketamine and investigate potential use for alcohol addiction, anxiety, and other conditions. Observational studies and case reports indicate both promising applications and risks, and emphasize the importance of careful screening, counseling, and aftercare. Meta-analyses underscore that the body of evidence is still limited and that more large-scale, placebo-controlled studies are needed to establish long-term efficacy and safety.