A single dose of the psychedelic compound dimethyltryptamine (DMT), the active ingredient in ayahuasca, has shown significant improvements in depressive symptoms, according to a new study from Imperial College London. The phase 2a clinical trial tested DMT on adults living with long-term depression and found notable symptom reduction compared with a placebo.
The study involved 34 participants who had experienced depression for an average of 10.5 years. Half received a 21.5-milligram intravenous dose of DMT over 10 minutes, accompanied by psychotherapeutic support, while the other half received a placebo. Researchers reported that participants treated with DMT experienced a marked decrease in depressive symptoms after two weeks, with effects lasting up to three months.
DMT’s rapid metabolism gives it a short half-life of about five minutes, allowing for shorter therapeutic sessions, which may improve convenience and reduce treatment costs. The trial also found the treatment to be generally well-tolerated, with no serious adverse events reported. Most side effects were mild or moderate, primarily pain at the injection site.
Experts caution that while the results are encouraging, further research is required. “There may be a risk of negative experiences during the psychedelic session that could be frightening or traumatising,” said James Stone, professor of psychiatry at Brighton and Sussex Medical School. He added that certain groups may be more susceptible to adverse effects and further studies are needed to determine their frequency.
Depression affects approximately 332 million people worldwide, according to the World Health Organization. In Europe, more than 25 million individuals are estimated to live with depressive disorders. Current treatments include antidepressants, particularly selective serotonin reuptake inhibitors (SSRIs), and psychotherapy. However, the study authors highlighted that SSRIs often provide insufficient relief or unacceptable side effects. Around 20 to 30 percent of patients with major depressive disorder develop treatment-resistant depression, failing to respond to at least two antidepressants.
The study suggests that psychedelic compounds such as DMT could offer a new avenue for treatment. While no psychedelic therapies currently have full marketing approval from the European Medicines Agency, research and compassionate use programmes allow limited access.
Notably, the Czech Republic recently became the first European Union country to legalise medical psilocybin for psychotherapy, effective 1 January 2026. The treatment is reserved for patients with treatment-resistant depression or severe, non-psychotic mental deterioration, including cancer-related conditions. Only certified psychiatrists and psychotherapists with specialised psychedelic training can administer it in approved facilities.
The trial marks an early step in exploring the antidepressant potential of psychedelics, signalling a growing interest in alternative treatments for patients unresponsive to conventional therapies.
