Studies of hallucinogenic drugs on the resting brain show some consistent findings: psilocybin, LSD, and ayahuasca all decrease cerebral blood flow and increase global functional connectivity in the precuneus and thalamus. LSD also consistently reduces functional connectivity within distinct resting state networks. However, results for connectivity between networks and blood flow in other brain regions show little convergence. These studies are limited by small sample sizes and potential bias from unspecific drug effects on physiology and the vascular system. Current evidence suggests neuroimaging may help reveal the neural correlates of hallucinogenic effects.
Adding a daily 30-day mindfulness mobile app (Headspace) to standard treatment helped reduce depression severity more than standard treatment alone in people with major depressive disorder. In a randomized trial with 83 patients, those using the app showed a significantly greater decrease in clinician-rated depression scores (HDRS) and lower systolic blood pressure after one month. Both groups improved from partial remission at hospital discharge, but the app group improved more. The total dropout rate was 29%. Short-term app-based mindfulness appears beneficial as a supplement to usual care.
Intranasal racemic ketamine is non-inferior to esketamine for reducing depression symptoms in adults with treatment-resistant depression, with comparable symptom improvement over four weeks. However, remission rates were higher with esketamine (38.7%) than with racemic ketamine (15.6%), and racemic ketamine failed to meet non-inferiority for remission. Safety profiles were similar, though racemic ketamine caused slightly more transient blood pressure elevations. Racemic ketamine may be a cost-effective alternative where esketamine access is limited, but higher remission with esketamine warrants further study.