Emotional symptoms in children: The effect of maternal depression, life events, and COMT genotype.

Early adversity predicts anxiety and depression but variation in response to adversity is not understood. We investigated whether association between early adversity and emotional symptoms in young children differs according to variation of the COMT gene. The main outcome measure was the emotionality subscale of the Strengths and Difficulties Questionnaire (SDQ) completed by mothers for 8,431 children aged 6-7 years old in the Avon Longitudinal Study of Parents and Children. Adversity measures included exposure to maternal postpartum depressive symptoms and adverse life events for children. DNA from the children was genotyped for five COMT polymorphisms including the COMT Val158Met locus. Maternal depression increased the odds of high emotionality in the children, (OR 1.99, 95% CI 1.73-2.29, P < 0.001) as did life events score, (OR 1.21 for each s.d. increase in life event score, 95% CI 1.15-1.27, P < 0.001). There was no main effect of Val158Met genotype on emotional symptoms (OR for effect of each copy of the methionine allele was 1.04, 95% CI 0.97-1.10, P = 0.284). The relationship between adversity and emotional symptoms did not vary by genotype (G x E for maternal depression chi(2) = 3.17, P = 0.205; G x E for life events chi(2) = 1.69, P = 0.430). There was no main effect of COMT haplotype, nor was there an interaction with adversity. Early adversity predicts emotional symptoms in children aged 6-7 years. Although some studies indicate a role for COMT in emotionality, anxiety, and depression in adults, no direct effect or interaction of COMT genotype was observed in this large sample of young children.