A Systematic Review of Effectiveness of Omega-3 Fatty Acid Supplementation on Symptoms, Social Functions, and Neurobiological Variables in Schizophrenia

Background: Disturbance of lipid, particularly omega-3 polyunsaturated fatty acid (PUFA), metabolism is associated with the etiology and symptoms of schizophrenia. Numerous clinical studies have tried to evaluate whether omega-3 PUFA supplementation can ameliorate the disorder, but the results are inconclusive. Objectives: This systematic review integrates and refines the research evidence of the effectiveness of omega-3 PUFA nutritional supplementation on schizophrenia during the different developmental phases of the disease (prodromal, first-episode, and chronic phases) and examines whether different developmental stages modulate the efficacy of omega-3 PUFA supplementation. Data Sources: Scientific articles from 2000 to 2020 in PubMed/Medline, Allied Health Literature, PsychINFO, and SCOPUS following the Preferred Reporting Items for Systematic Reviews guidelines. Methods: A systematic review was performed. We reviewed electronic databases and identified 1,266 clinical studies. Of these, 26 met the inclusion criteria. Results: The effectiveness of omega-3 dietary supplementation on symptoms varies among different phases of illness. Omega-3 supplementation significantly improves positive and negative symptoms at the prodromal phase, improves mainly the negative symptoms in patients with the first-episode, and effects symptoms partly in patients with chronic schizophrenia. Discussion: The effectiveness of omega-3 PUFA dietary supplementation is modulated by age, duration of untreated psychosis and illness, baseline levels of omega-3 fatty acids, and status of antioxidant capacity of patients. The important implications for psychiatric research and clinical practice developments as well as nursing care are presented and discussed.

Automated summary

The effectiveness of omega-3 PUFA supplementation on symptoms of schizophrenia varies depending on the different phases of the illness, with improvement in positive and negative symptoms during the prodromal phase, mainly improvement in negative symptoms in first-episode patients, and partial effects on symptoms in patients with chronic schizophrenia.