The NEURAPRO Biomarker Analysis: Long-Chain Omega-3 Fatty Acids Improve 6-Month and 12-Month Outcomes in Youth at Ultra-High Risk for Psychosis

Abstract

Background: NEURAPRO was a multicenter, double-blind, randomised, placebo-controlled trial RCT of long-chain omega-3 polyunsaturated fatty acids (n-3 PUFA) ('fish oil') therapy provided for 6 months in individuals at ultra-high risk (UHR) for psychotic disorders, followed by an additional 6-month follow-up period. The study was conducted in 10 specialized early psychosis treatment services in Australia, Asia, and Europe, in 304 participants who received either n-3 PUFA together with cognitive behavioral case management (CBCM) or placebo with CBCM. In the intention to treat analysis, NEURAPRO failed to replicate findings of a previous single-center study. Although the RCT design is placed at the top of the evidence hierarchy, this methodology has limitations in fish oil RCTs, since the test agent is not only present in the intervention group but n-3 PUFA are present in the diet and in the body tissue of all participants, potentially influencing outcomes.

Methods: We conducted a biomarker analysis in NEURAPRO participants to determine if n-3 PUFA (eicosapentaenoic acid, EPA; docosahexaenoic acid, DHA; n-3 index; EPA+DHA) levels measured in erythrocyte membranes at baseline and at month 6 (end-of supplementation) predicted clinical outcomes 6 and 12 months after study entry in the participants irrespective of their original treatment group allocation in the trial.

Findings: Of the 304 participants, 285 (94%) had biomarker data at baseline and 218 (72%) participants had biomarker data at baseline and a subsequent time point (209 at month 6; 9 at transition to psychosis). Increases of the n-3 index, EPA and DHA consistently predicted less severe psychopathology and better functioning at both follow-up time points. Higher baseline levels and increases of the n-3 index also predicted overall clinical improvement at month 6 (n-3 index baseline: adjusted odds ratio (95%CI)=1.79 (1.30-2.48); n-3 PUFA increase: adjusted odds ratio (95%CI)=1.43 (1.16-1.76) and at month 12 (n-3 index baseline: adjusted odds ratio (95%CI)=2.60 (1.71-3.97); n-3 PUFA increase: adjusted odds ratio (95%CI)=1.36 (1.06-1.74). The transition to psychosis rate was lower than expected in this study (5.0% at month 6; 10.1% at month 12). No association was observed between n-3 PUFA measures and transition to psychosis.

Interpretation: These data suggest that n-3 PUFA can exert protective and therapeutic effects in UHR individuals. This finding may have implications for early intervention and clinical treatment guidelines since n-3 PUFA supplementation can easily and safely be used in a wide variety of settings, from primary care to specialist services.

Trial Registration: The trial was registered at the Australia and New Zealand Clinical Trials Registry (ID 12608000475347).

Funding Statement: This work was supported by grant 07TGF-1102 from the Stanley Medical Research Institute, grant 566529 from the NHMRC Australia Program (Drs McGorry, Hickie, and Yung, and Amminger), and a grant from the Colonial Foundation. Drs Amminger and Yung were supported by NHMRC Senior Research Fellowships 1080963 and 566593, respectively; and Dr Nelson was supported by NHMRC Career Development Fellowship 1027532. Dr McGorry was supported by Senior Principal Research Fellowship 1060996 from the National Health and Medical Research Council of Australia (NHMRC).

Declaration of Interests: Drs Amminger, Hickie, Yung, and Nelson have received National Health and Medical Research Council (NHMRC) funding. Dr McGorry reported receiving grant funding from National Alliance for Research on Schizophrenia and Depression and unrestricted research funding from AstraZeneca, Eli Lilly, Janssen-Cilag, Pfizer, and Novartis, as well as honoraria for educational activities with AstraZeneca, Eli Lilly, Janssen-Cilag, Pfizer, Bristol-Myers Squibb, Roche, and the Lundbeck Institute. No other conflicts were reported.

Ethics Approval Statement: The National Health and Medical Research Council of Australia (NHMRC) National Statement on Human Research was adhered to and appropriate ethical approval was obtained by each site (Melbourne, Australia: Melbourne Health Research Ethics Committee; Sydney, Australia: Sydney South West Area Health Service Ethics Review Committee; Basel, Switzerland: Ethics Commission for Basel; Zurich, Switzerland: Cantonal Ethics Commission Zurich; Jena, Germany: University Clinic Jena Ethics Commission; Copenhagen, Denmark: Capital Region Research Ethics Committee; Hong Kong: Institutional Review Board of the University of Hong Kong/Hospital Authority Hong Kong West Cluster; Vienna, Austria: Medical University of Vienna Ethics Commission; Singapore: National Healthcare Group Domain Specific Review Board; and Amsterdam, the Netherlands: Academic Medical Centre Medical Ethics Committee). Written informed consent was obtained for those younger than 17 years, parental or guardian consent was sought. Participants received financial compensation.

Keywords: Ultra-high risk for psychotic disorders; eicosapentaenoic acid, EPA; docosahexaenoic acid, DHA; omega-3 index; biomarker analysis; randomised, placebo-controlled trial; NEURAPRO