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©The Author(s) 2025. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Methodol. Dec 20, 2025; 15(4): 104664
Published online Dec 20, 2025. doi: 10.5662/wjm.v15.i4.104664
Published online Dec 20, 2025. doi: 10.5662/wjm.v15.i4.104664
Current state of nutritional psychiatry: A scoping review of randomized controlled trials
Takahiko Nagamine, Department of Psychiatric Internal Medicine, Sunlight Brain Research Center, Hofu 7470066, Yamaguchi, Japan
Author contributions: Nagamine T designed and conceived the study, collected the data, analyzed and interpreted the results, drafted the manuscript, and has read and agreed to the published version of the manuscript.
Conflict-of-interest statement: The authors have no conflicts of interest to declare.
PRISMA 2009 Checklist statement: The authors have read the PRISMA 2009 Checklist, and the manuscript was prepared and revised according to the PRISMA 2009 Checklist.
Open Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: https://creativecommons.org/Licenses/by-nc/4.0/
Corresponding author: Takahiko Nagamine, MD, PhD, Department of Psychiatric Internal Medicine, Sunlight Brain Research Center, 4-13-18 Jiyugaoka, Hofu 7470066, Yamaguchi, Japan. anagamine@yahoo.co.jp
Received: December 28, 2024
Revised: February 25, 2025
Accepted: March 4, 2025
Published online: December 20, 2025
Processing time: 220 Days and 11.7 Hours
Revised: February 25, 2025
Accepted: March 4, 2025
Published online: December 20, 2025
Processing time: 220 Days and 11.7 Hours
Core Tip
Core Tip: The number and quality of randomized controlled trials (RCTs) in the field of nutritional psychiatry remain inadequate. The relationship between nutrition and psychiatric disorders is challenging to demonstrate causally in RCTs due to the multitude of confounding factors and the relatively modest effect sizes observed. To enhance the evidence base in nutritional psychiatry, it would be beneficial to utilize not only RCTs but also data from Mendelian randomization studies and fundamental research, with the aim of elucidating the underlying mechanisms.