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Open Access Research article

No interaction between serotonin transporter gene (5-HTTLPR) polymorphism and adversity on depression among Japanese children and adolescents

Akemi Tomoda1*, Shota Nishitani2, Naomi Matsuura3, Takashi X Fujisawa12, Junko Kawatani4, Daiki Toyohisa4, Mai Ono4 and Kazuyuki Shinohara2

Author Affiliations

1 Research Center for Child Mental Development, University of Fukui, Fukui, Japan

2 Department of Neurobiology& Behavior Unit of Basic Medical Sciences Course of Medical & Dental Sciences, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan

3 School of Education, Tokyo University and Graduate School of Social Welfare, Tokyo, Japan

4 Department of Child Development, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan

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BMC Psychiatry 2013, 13:134  doi:10.1186/1471-244X-13-134

Published: 10 May 2013

Abstract

Background

Identification of gene × environment interactions (G × E) for depression is a crucial step in ascertaining the mechanisms underpinning the disorder. Earlier studies have indicated strong genetic influences and numerous environmental risk factors. In relation to childhood and adolescent depression, evidence is accumulating that the quality of the parental environment is associated with serotonin biology in children. We hypothesized that maternal depression is a crucial environmental risk factor associated with serotonin-regulating genes.

Methods

This study was designed to ascertain the G × E interaction for diagnosis of depression in a Japanese pediatric sample. DNA samples from 55 pediatric patients with depression and 58 healthy schoolchildren were genotyped for the 5-HTT (2 short (S) alleles at the 5-HTT locus) promoter serotonin-transporter-linked polymorphic region (5-HTTLPR) polymorphism. We examined whether an adverse parental environment, operationalized as the mother’s history of recurrent major depressive disorder, interacts with 5-HTTLPR polymorphism to predict patients’ depression symptoms.

Results

Binary logistic regression analyses revealed that maternal depression (adversity), gender, and FSIQ significantly affect the diagnosis of depression among children and adolescents. However, no main effect was found for adversity or genotype. Results of multivariable logistic regression analyses using stepwise procedure have elicited some models with a good fit index, which also suggests no interaction between 5-HTTLPR and adversity on depression.

Conclusions

To assess G × E interaction, data obtained from children and adolescents who had been carefully diagnosed categorically and data from age-matched controls were analyzed using logistic regression. Despite an equivocal interaction effect, adversity and gender showed significant main effects.

Keywords:
Child depression; Gene-by-environment (G × E) interaction; Serotonin transporter gene (5-HTTLPR) Polymorphism; Early adversity