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.
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.