Social supports and serotonin transporter gene moderate depression in maltreated children

Abstract

In this study, measures of the quality and availability of social supports were found to moderate risk for depression associated with a history of maltreatment and the presence of the short (s) allele of the serotonin transporter gene promoter polymorphism (5-HTTLPR). The present investigation (i) replicates research in adults showing that 5-HTTLPR variation moderates the development of depression after stress, (ii) extends the finding to children, and (iii) demonstrates the ability of social supports to further moderate risk for depression. Maltreated children with the s/s genotype and no positive supports had the highest depression ratings, scores that were twice as high as the non-maltreated comparison children with the same genotype. However, the presence of positive supports reduced risk associated with maltreatment and the s/s genotype, such that maltreated children with this profile had only minimal increases in their depression scores. These findings are consistent with emerging preclinical and clinical data suggesting that the negative sequelae associated with early stress are not inevitable. Risk for negative outcomes may be modified by both genetic and environmental factors, with the quality and availability of social supports among the most important environmental factors in promoting resiliency in maltreated children, even in the presence of a genotype expected to confer vulnerability for psychiatric disorder.

Figures

Fig. 1.

Predictors of depression. Group status (maltreatment vs. CC), 5-HTTLPR genotype (l/l vs. l/s vs. s/s), and social supports (high vs. low) were all significant predictors of children's depression scores in the GEE analysis (P < 0.05, all main effects).

Fig. 2.

Gene–maltreatment interaction in predicting depression in children. The interaction between the 5-HTTLPR genotype and maltreatment history was significant (P < 0.01). The s/s genotype conferred a significant vulnerability for depression, but only in the maltreated children.

Fig. 3.

Depression scores of high-, moderate, and low-risk children in the maltreatment and CC groups. There was a significant three-way interaction among maltreatment, genotype, and social supports in predicting children's depression scores (P < 0.0001). Maltreated children with the s/s genotype and low social supports had markedly elevated depression scores, ratings that were approximately twice as high as those of CCs with the same genotype and social support profile (high-risk CC, 15.0 ± 8.3; high-risk maltreated, 30.0 ±12.3). However, although the combination of the s/s genotype and low social supports was associated with very high depression scores in the maltreated cohort, maltreated children with only one of these risk factors had only modest increases in their depression scores compared with CCs (moderate-risk CC, 12.8 ± 8.8; moderate-risk maltreated, 15.3 ± 9.7).

Fig. 4.

Effect of social support availability on depression scores in maltreated children. The relative availability of maltreated children's social supports also affected their depression scores. Except for maltreated children with the s/s genotype, maltreated children with monthly or more frequent contact with their primary support had relatively low depression scores (which were, on average, only 3 points higher than the mean depression score of the CC group). The depression scores of the maltreated children with the s/s genotype that had relatively regular contact with their primary supports were 67% higher than those of the maltreated children with less vulnerable genotypes who had comparable contact with their supports. However, the maltreated children with the s/s genotype and semiannual or less frequent contact with their primary support had the highest depression scores. Their depression scores were, on average, 9 points higher than those of the maltreated children with the s/s genotype that had monthly or more frequent contact with their supports and 18 points higher than those of the maltreated children with the less vulnerable genotypes that had more regular contact with their supports.