Omega-3 fatty acids in mental disorders: from neurobiological and metabolic mechanisms to therapeutic potential

Nutritional psychiatry is an emerging field. Micro- and macro-nutrients play a role in energy metabolism and the regulation of inflammation; particularly, an insufficient dietary intake of omega-3 fatty acids and an imbalanced intake of omega-6/omega-3 fatty acids, with a shift toward increased inflammation, are of relevance for the pathophysiology of mental disorders. This review summarizes evidence on the role of omega-3 fatty acids in the pathophysiology of mental disorders (schizophrenia, affective and anxiety disorders, post-traumatic stress disorder, and eating disorders), neurodevelopmental disorders (attention-deficit/hyperactivity disorder and autism spectrum disorder) and neurodegenerative disorders (Alzheimer's disease) and explores potential treatment implications. In addition, the underlying neurobiological mechanisms through which omega-3 fatty acids might exert a protective effect are also discussed. Despite methodological variability and heterogeneous results, an increasing body of evidence suggests that omega-3 deficiency and altered fatty acid profiles are modifiable risk factors and potential biomarkers for mental disorders. The integration of omega-3 supplementation as an adjuvant to state-of-the-art therapy offers the potential for a low-risk intervention with meaningful clinical outcomes. However, clinical monitoring is recommended to avoid adverse effects and to adjust the dosage according to individual and disease-specific factors.