Neuropsychopharmacology : official publication of the American College of Neuropsychopharmacology
April 1, 2024
Thomas J Kelly, Emma M Bonniwell, Lianwei Mu et al.
26 citations
4-OH-DiPT, a fast-acting and shorter-lasting derivative of psilocybin, reduces learned fear responses in mice by enhancing inhibitory signaling in the brain. It activates 5-HT2A receptors on interneurons in the basolateral amygdala, increasing GABAergic inhibition of principal neurons. In female mice, 4-OH-DiPT before extinction training reduced freezing to conditioned cues and later decreased avoidance behaviors in several tests, while male mice showed no significant differences. The compound acts as a near full agonist at 5-HT2A receptors and has comparable activity at mouse and human 5-HT2A/2B/2C receptors. These findings suggest a potential mechanism for suppressing learned fear.
iScience
January 16, 2026
Amir Valizadeh, John D Roache, Xinyu Zhang et al.
2 citations
Post-traumatic stress disorder varies greatly in its clinical and biological features, making treatment difficult. The largest randomized trial of ketamine for PTSD found no overall benefit over placebo, highlighting the need to identify which patients might respond. Using pre-treatment blood DNA methylation profiles and clinical data from that trial, machine learning models predicted treatment response. A model based on 1,208 methylation sites outperformed models using only clinical variables, and combining both data types improved accuracy further. The methylation-derived score identified responders with 92.9% accuracy. Predictive methylation sites were near genes involved in glutamatergic signaling, immune regulation, and known PTSD risk loci, suggesting peripheral DNA methylation patterns can guide precision pharmacotherapy for PTSD.
Nature Communications
April 8, 2026
Thomas J. Kelly, Xiaojie Liu, Yao Huang et al.
High doses of cannabinoids like THC produce anxiety, but the underlying brain mechanisms were unclear. This study in mice identifies a specific neural circuit—projections from the anterior cingulate cortex to the dorsomedial striatum—where cannabinoid signaling promotes anxiety and aversion. Activating this circuit reduces anxiety, whereas cannabinoids suppress its activity via CB1 receptors. Deleting CB1 receptors specifically in this circuit reduced both innate anxiety and conditioned place aversion to THC. These findings reveal a circuit-level mechanism for cannabinoid-induced anxiety.