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Major Depressive Disorder (MDD) is a mood disorder defined in the DSM-5-TR by one or more Major Depressive Episodes lasting at least two weeks, during which five or more symptoms — including at least one of depressed mood or markedly diminished interest or pleasure (anhedonia) — occur nearly every day and cause clinically significant distress or impairment, in the absence of any history of a manic or hypomanic episode (DSM-5-TR criteria for Major Depressive Disorder, NCBI Bookshelf).
Within nutritional psychology, MDD is one of several mood-related outcomes examined in relation to dietary patterns, eating behavior, and microbiota–gut–brain pathways. Dietary approaches do not replace psychiatric, psychological, or medical treatment. If you or someone you know is experiencing suicidal ideation, contact the U.S. 988 Suicide & Crisis Lifeline or an international line via Find A Helpline.
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Editorial responsibilityReferences and further reading
- Fehse, L., Ribeiro, A. H., Winter, N. R., Thanarajah, S. E., Fisch, L., Welzel, M., Bang, C., Meinert, S., Flinkenflügel, K., Borgers, T., Goltermann, J., Leehr, E. J., Bloemendaal, M., Natasha, E. E., Mulder, D., Arias Vasquez, A., Stein, F., Thomas-Odenthal, F., Usemann, P., Teutenberg, L., … Hahn, T. (2026). From gut to brain: data-driven evidence suggests causal contribution of gut-microbiota to major depressive disorder in humans. Gut microbes, 18(1), 2718589. https://doi.org/10.1080/19490976.2026.2718589 View source
- Mestrom, A., Charlton, K. E., Thomas, S. J., Larkin, T. A., Walton, K. L., Elgellaie, A., & Kent, K. (2023). Higher anthocyanin intake is associated with lower depressive symptoms in adults with and without major depressive disorder. Food Science & Nutrition, 12(3), 2202. https://doi.org/10.1002/fsn3.3850 View source
How to cite this entry
Encyclopedia of Nutritional Psychology. (2026). Major Depressive Disorder (MDD). The Center for Nutritional Psychology.
https://www.nutritional-psychology.org/encyclopedia/major-depressive-disorder-mdd/Know a term that belongs in the Encyclopedia?
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