Digit span improvement following long chain omega-3 polyunsaturated fatty acids supplementation: A preliminary study

Background: Neurocognitive deficits are reported in participants with juvenile Bipolar Disorder (JBD) including digit span. Digit span is an indicator of short-term auditory memory, working memory, concentration and attention. Long-chain omega-3 polyunsaturated fatty acids (LCn-3PUFA) are important to brain development and functioning, however, their effects on neurocognitive function are not clear. Objective: To examine the effectiveness of LCn-PUFA supplementation on digit span ability in children and adolescents with JBD. Design: Fifteen participants with JBD (9-18 yr) consumed LCn-3PUFA supplements containing 360 mg day-1 eicosapentaenoic acid (EPA) and 1560 mg day-1 docosahexaenoic acid (DHA) for 6 weeks in an open-label preliminary study. Digit span and red blood cell (RBC) LCn-3PUFA concentrations were assessed prior to and following supplementation. Outcomes: Digit Backwards (2.3 ± 0.45 vs 3.2 ± 0.46, p = 0.010) and Scaled Overall Digit Span (11.1 ± 0.70 vs 12.1 ± 0.72, p = 0.046) significantly improved following supplementation. RBC DHA was significantly positively correlated to longest digit span backwards (r = 0.84, p < 0.001) and overall digit span scaled scores (r = 0.62, p = 0.010). Conclusions: Supplementation with LCn-3PUFA was associated with improvements in neurocognitive functioning. Further studies should examine other neuropsychological outcomes in a larger sample in a randomised controlled trial (RCT) and whether cognitive deficits associated with JBD can be prevented.