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Chadi G Abdallah

Menninger Department of Psychiatry & Behavioral Sciences, Baylor College of Medicine, Houston, TX, USA.

4 papers in the library · 142 citations · publishing 2022-2026

Papers

International pooled patient-level meta-analysis of ketamine infusion for depression: In search of clinical moderators

Molecular Psychiatry September 7, 2022 Rebecca B Price, Nicholas Kissel, Andrew Baumeister et al. 80 citations

Ketamine given intravenously rapidly reduces depressive symptoms, with effects lasting at least a week. In an analysis of 17 randomized controlled trials with 809 participants, the benefit over placebo was larger for patients who had already failed two or more prior antidepressant trials. However, no patient-level clinical or demographic characteristics—such as age, sex, or diagnosis—could predict who would respond best, limiting the ability to personalize ketamine prescriptions. The findings confirm ketamine's broad effectiveness for depression but show that precision medicine approaches cannot yet guide treatment decisions.

The potential of ketamine for posttraumatic stress disorder: a review of clinical evidence.

Therapeutic advances in psychopharmacology January 1, 2023 Anya Ragnhildstveit, Jeremy Roscoe, Lisa C Bass et al. 49 citations

PTSD has few effective pharmacological treatments, and trauma-focused psychotherapies are limited by provider shortages and low patient engagement, often leading to chronic illness and reduced quality of life. Ketamine, an NMDA receptor antagonist already indicated for major depression with rapid antidepressant effects, shows transdiagnostic potential. A synthesis of clinical evidence—including case reports, chart reviews, open-label studies, and randomized trials—reveals high heterogeneity in presentation and treatment approach but encouraging signals of safety, efficacy, and durability. Future research directions are discussed.

Challenges and rewards of in vivo synaptic density imaging, and its application to the study of depression.

Neuropsychopharmacology : official publication of the American College of Neuropsychopharmacology November 1, 2024 Ruth H Asch, Chadi G Abdallah, Richard E Carson et al. 11 citations

A review describes the development of PET radiotracers targeting the synaptic vesicle glycoprotein 2A (SV2A), which allows measurement of synaptic density in living brains. In depression, lower SV2A density is found in people with significant depressive symptoms. A ketamine challenge was used to examine synaptogenesis in vivo. The authors stress the value of combining clinical imaging with animal model studies, presenting preliminary findings from chronic stress models. Methodological challenges and future directions for SV2A imaging, possibly alongside other neural markers, are discussed.

Combining DNA methylation features and clinical characteristics predicts ketamine treatment response for PTSD.

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.