Psychophysiology
March 27, 2021
Sebastian Olbrich, Katrin H. Preller, Franz X. Vollenweider
34 citations
Lysergic acid diethylamide (LSD) predominantly increases sympathetic nervous system activity, while the serotonin 2A receptor antagonist ketanserin counteracts this effect by increasing parasympathetic tone. In a randomized, placebo-controlled crossover trial, heart rate variability measures showed that sympathetic activity was positively associated and parasympathetic activity negatively associated with the subjective psychedelic effects of LSD. Additionally, placebo heart rate variability measures predicted subjective experiences after LSD intake. This association between trait autonomic nervous system activity and LSD-induced subjective experiences may serve as a candidate biomarker for the effectiveness of LSD in treating psychopathological conditions.
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.
Journal of affective disorders
November 22, 2025
Carlos Trenado, Erich Seifritz, Sebastian Olbrich et al.
4 citations
Frontal EEG recordings before treatment with ketamine or esketamine in 43 people with major depressive disorder revealed that those who later responded to the medication had increased functional connectivity (measured by phase locking value and phase lag index) and decreased entropy (Renyi and Tsallis) compared to non-responders. Aperiodic spectral parameters were lower in responders but did not predict response. These EEG measures showed moderate predictive accuracy, with area under the ROC curve values of 0.7065 for Renyi entropy, 0.7101 for Tsallis entropy, and 0.7283 for phase lag index, suggesting frontal EEG patterns may serve as biomarkers for identifying individuals likely to benefit from (es)ketamine treatment.
Journal of affective disorders
October 1, 2025
Weng-Lam Chan, Sebastian Olbrich, Xinwen Jiang et al.
3 citations
Ketamine, a drug that blocks NMDA receptors and is thought to boost neuroplasticity, increased whole-brain EEG signal complexity during infusion in patients with major depressive disorder (MDD), most of whom had treatment-resistant depression. Higher complexity at the end of infusion predicted less symptom improvement the next day, while lower occipital complexity before treatment predicted a favorable response. A logistic model using occipital complexity had moderate predictive accuracy. No changes were seen in a different complexity measure, suggesting it is not useful as a biomarker. Occipital EEG complexity may help predict which patients will benefit from ketamine therapy.
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.
Progress in Neuro-Psychopharmacology and Biological Psychiatry
January 1, 2026
Cheng-Teng Ip, Sebastian Olbrich, Mateo de Bardeci et al.
1 citation
In a double-blind, randomized, crossover, placebo-controlled trial with 25 healthy adults, psilocybin (10–20 mg oral) decreased EEG power in slow frequency bands (theta and alpha) and increased power in fast frequency bands (beta, gamma1, gamma2) compared to placebo. Connectivity within the default-mode network and localized parietal network increased under psilocybin. Changes in EEG power and connectivity correlated positively with subjective experiences measured by the Altered States of Consciousness Questionnaire. Baseline EEG features predicted subjective alterations, suggesting that specific brain activity patterns could serve as biomarkers for tailoring psilocybin therapy.
Therapeutische Umschau. Revue therapeutique
April 1, 2025
Tobias Bracht, Daniela Hubl, Kristina Adorjan et al.
1 citation
For patients with difficult-to-treat depression who do not respond to at least two antidepressant trials, remission rates are significantly lower than the 67% seen with initial or secondary pharmacological treatment. Brain stimulation procedures and novel substances offer innovative and effective options to complement standard therapies. This overview covers repetitive transcranial magnetic stimulation, electroconvulsive therapy, ketamine/esketamine, transcranial direct current stimulation, deep brain stimulation, and psychedelic-assisted psychotherapy, with an outlook on individualized, procedure-specific indications.
Psychotherapy and psychosomatics
June 19, 2026
Judith Rohde, Tyler M Moore, Kathryn Walker et al.
A systematic review and individual participant data meta-analysis of 12 studies (533 participants) found that higher baseline PTSD severity was the most robust predictor of symptom reduction after combined ketamine and psychotherapy. More psychotherapy sessions, more ketamine sessions, and shorter treatment duration were also associated with greater improvement, but these findings are tentative because most studies were of poor quality. The analysis showed that for each additional psychotherapy session, PTSD symptoms improved by an average of 1.03 points on the PCL-5, and for each additional ketamine session, improvement was 1.15 points. The results require confirmation in well-designed prospective trials.
Therapeutic advances in psychopharmacology
January 1, 2026
Yujuan Liu, Xiaorong Liu, Sebastian Olbrich et al.
Ketamine, a rapid-acting antidepressant for treatment-resistant depression, may work by altering the brain's excitation-inhibition balance, measurable via the aperiodic exponent of EEG power spectra. In a placebo-controlled trial of 24 patients with major depressive disorder, ketamine infusion significantly reduced the aperiodic exponent across the scalp. Patients who responded to treatment had steeper pretreatment occipital aperiodic exponents, which predicted better outcomes. A meta-analysis within the study revealed substantial variability in ketamine's effect on this measure. The occipital aperiodic exponent may serve as a biomarker for predicting antidepressant response, but further large-scale studies are needed.
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.