Adolescence is an important period for cognitive maturation and emotional regulation, and this age group is particularly vulnerable to developing depression. Diets rich in fruits and vegetables have been associated with decreased risk of developing depressive disorders across the lifespan, maybe due to the high flavonoid content of these foods. Previously, we have shown increases in transient positive affect (PA) in both children and young adults 2 h after administration of a wild blueberry (WBB) intervention. Here, using a randomised double-blind, placebo-controlled trial, we investigated the effects of 4 weeks, daily WBB supplementation (containing about 253 mg anthocyanins) on transient and chronic mood in adolescents. Healthy 12–17-year old (n 64, thirty-five females) participants were randomly assigned to receive either a WBB or matched placebo supplementation. Depression and anxiety symptoms were assessed before and after the intervention period using the Mood and Feeling Questionnaire and Revised Child Anxiety and Depression Scale. Transient affect was assessed before, 2 weeks and at 4 weeks using PA and negative affect. Following the intervention period, there were significantly fewer self-reported depression symptoms in participants who were supplemented with WBB compared with placebo (P = 0·02, 95 % CI –6·71, –5·35). There was no between-group effect on anxiety symptoms or on transient affect. Further investigation is required to identify specific mechanisms that link flavonoids consumption and mood. If replicated, the observed effects of WBB supplementation may be a potential prevention strategy for adolescent depression and may have benefits for public mental health.

People who have depression have difficulty recalling specific autobiographical information (Sumner, (2011) The mechanisms underlying overgeneral autobiographical memory: An evaluative review of evidence for the Ca R-FA-X model. Clinical Psychology Review, 3231(1), 34-48). This is called overgeneral autobiographical memory (OGM) and is associated with the development and persistence of depression. Williams, Barnhofer, Crane, Hermans, Raes, Watkins, & Dalgleish (2007 Autobiographical memory specificity and emotional disorder. Psychological Bulletin, 133(1), 122-148) proposed that OGM is maintained by three mechanisms: capture and rumination (CaR), functional avoidance (FA), and impaired executive control (X), and integrated these into the CaR-FA-X model. The aim of this study was to assess OGM and test the CaR-FA-X model in adolescents with low mood. We recruited 29 young people aged 12-17 with elevated symptoms of depression and 29 with minimal symptoms of depression, matched for gender and age. After controlling for IQ, adolescents with elevated depression retrieved fewer specific memories, ruminated more, and had poorer working memory and verbal fluency than adolescents with minimal depression. The groups did not differ on measures of inhibition or functional avoidance. The CaR-FA-X model was therefore partially supported. These results confirm that there is a relationship between low mood and OGM in young people and that OGM may arise as consequence of impaired working memory and verbal fluency and cognitive interference due to rumination.