Omega-3 index as risk factor in psychiatric diseases: a narrative review.
Level 5 - mechanism / opinion, no new human data
Narrative review synthesizing existing literature without meta-analytic pooling
PubMed 37575565 · doi:10.3389/fpsyt.2023.1200403
What was done
Authors conducted a narrative review searching PubMed, Scopus, and Web of Science using PRISMA search and selection procedures to assess associations between the omega-3 index (RBC percentage of EPA and DHA) and psychiatric conditions. They included 36 English-language original research studies covering postpartum depression (3), major depression (15), bipolar disorder (4), major depression and bipolar disorder (1), schizophrenia and major depression (1), schizophrenia and other psychosis (5), and dementia (7).
What was found
Thirty of the 36 studies found either significant differences in the omega-3 index between patients and controls or inverse relationships between the index and disease severity. Based on these findings, the authors proposed risk thresholds for Western populations of 4% to 5% for major depression and dementia, 5% for postpartum depression, and 4% for psychosis transition. The abstract reports no pooled numerical effect sizes or confidence intervals.
Why it matters
It aggregates evidence linking erythrocyte omega-3 levels to major psychiatric disorders and proposes specific biomarker cutoff ranges for risk stratification.
Limits
The paper is a narrative review without quantitative meta-analysis, forest plots, or formal risk-of-bias grading across studies. The underlying evidence is observational, preventing causal inference, and proposed cutoffs are descriptive thresholds rather than prospectively validated targets.
Cited by
- supports A lower omega-3 index is associated with an increased risk of depression.