Two recent papers associated candidate genes with brooding rumination, a possible cognitive endophenotype for depression, in children ages 8-14 years.Stone et al. reported that BDNF val66met polymorphism predicted brooding in adolescence.Woody et al. reported that children carrying at least one copy of a CRHR1 TAT haplotype reported less brooding than their peers in the presence of maternal depression.
The three-way interaction between the functional polymorphism in the serotonin transporter gene linked promoter region, the val66met polymorphism in the brain-derived neurotrophic factor gene, and childhood adversity in the prediction of depression in children, reported by Kaufman and colleagues in 2006, has only been confirmed in adult samples.