Frontiers in Behavioral Neuroscience
December 3, 2021
Michael Colla, Hanne Scheerer, Steffi Weidt et al.
9 citations
Ketamine's rapid antidepressant effects challenge traditional theories that focus on monoaminergic pathways. Current research explores mechanisms including glutamatergic disinhibition, neurotrophic, and neuroplastic effects. Despite extensive study, ketamine has not yet led to new therapies beyond itself, and significant knowledge gaps and study limitations remain.
Behavioral sciences (Basel, Switzerland)
August 16, 2024
Judith Rohde, Elena Hickmann, Marco Buchmann et al.
7 citations
A pilot case series tested an eight-week program combining nasally administered ketamine (0.5 mg/kg) with trauma-focused psychotherapy for three individuals with chronic, treatment-resistant PTSD. Clinically relevant reductions in PTSD symptoms were observed, with CAPS-5 scores decreasing by an average of 18 points after treatment and 25 points at follow-up. Depressive symptoms also improved, with HAMD scores dropping by an average of 8.3 points after treatment and 9 points at follow-up. Additional benefits included reduced anxiety, fewer dissociations, and better emotion regulation. The ketamine was well tolerated and provided immediate relief from tension, anxiety, and common PTSD symptoms. The authors note that randomized controlled trials are needed to validate these findings.
Psychiatry research. Neuroimaging
July 1, 2025
Anna Monn, Corinne Eicher, Annia Rüesch et al.
2 citations
A higher percentage of EEG vigilance stage A1, a measure of brain activity, is associated with response to intravenous ketamine in major depression. In a phase-2 randomized controlled trial of oral prolonged-release ketamine for treatment-resistant depression, no significant interaction between response and treatment was found for this EEG marker. However, a small-scale meta-analysis showed a significant pooled mean difference between ketamine responders and non-responders. Applying a previously proposed A1 cutoff of 43% yielded chance-level prediction accuracy in the combined ketamine group but 75% accuracy in the 240 mg subgroup. Responders to 240 mg ketamine also showed more stable vigilance over time. These findings support EEG vigilance as a predictive biomarker for treatment outcomes in depression, though further validation is needed.
The Lancet Regional Health - Europe
December 10, 2025
Johannes Jungwirth, Samuel Westenhöfer, Helena D. Aicher et al.
In a retrospective analysis of medical records from 19 patients with treatment-resistant depression treated with psilocybin (20–35 mg) in one to four dosing sessions at a Swiss psychiatric hospital, depression severity decreased significantly. Montgomery–Åsberg Depression Rating Scale scores dropped from an average of 30.78 before treatment to 19.89 afterward, a large effect, and Beck Depression Inventory II scores fell from 32.33 to 23.28. Response and remission rates were 33.3% and 22.2% by the MADRS, and 27.8% and 27.8% by the BDI. No serious adverse events occurred. Response and remission rates were lower than those in previous controlled trials, and no additive effect of multiple dosing was found.
December 10, 2025
Johannes Jungwirth, Samuel Westenhöfer, Helena Aicher et al.
In a real-world clinical setting in Switzerland, 19 patients with treatment-resistant depression received one to four doses of psilocybin (20–35 mg). Depression severity, measured by the Montgomery–Åsberg Depression Rating Scale and the Beck Depression Inventory II, showed significant and clinically meaningful reductions from before to after treatment. Response rates were 33.3% and remission rates 22.2% on one scale; on the other, both were 27.8%. No serious adverse events occurred, and multiple dosing did not add benefit. These response and remission rates are lower than those seen in earlier controlled trials, but the findings provide some of the first real-world evidence for psilocybin's antidepressant effects.
European archives of psychiatry and clinical neuroscience
September 1, 2025
Golo Kronenberg, Georgios Schoretsanitis, Erich Seifritz et al.
Nitrous oxide (N2O) has been used since the 1700s and today is a significant greenhouse gas and ozone-depleting substance, though medical use contributes little to these effects. Its analgesic and anesthetic properties make it common in dentistry and surgery, and new research suggests antidepressant actions through NMDA antagonism and opioid effects. Larger clinical trials are needed to confirm its use as a rapid-acting antidepressant, and optimal dosing and duration remain unclear. Non-medical use has increased, with risks including asphyxia from acute use and vitamin B12 deficiency from chronic use, leading to conditions like megaloblastic anemia, venous thrombosis, myeloneuropathy, and skin pigmentation. Treatment requires stopping N2O use and administering parenteral vitamin B12; homocysteine and methylmalonic acid are helpful diagnostic tests.
BMJ open
July 16, 2025
Golo Kronenberg, Anna Bankwitz, Barbora Provaznikova et al.
Nitrous oxide (N2O) may offer rapid antisuicidal effects across mental health conditions, with its pharmacological action thought to involve NMDA antagonism and opioid effects. This protocol describes a single-centre pilot study of 85 psychiatric inpatients. In a double-blind, randomized, placebo-controlled design, the first 45-minute inhalation session delivers either 50% N2O with 50% oxygen or 50% oxygen plus air. Suicidal ideation is measured by the Beck Scale for Suicidal Ideation before and after inhalation. A second N2O inhalation one week later ensures all participants receive active treatment. A nested biomarker substudy using hair, blood, and EEG will explore mechanisms and prediction.