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Updated: Jul 12, 2026

The Forced Swim Test as a Model of Depressive-like Behavior
Published on: March 2, 2015
Early-emerging cognitive vulnerability to depression and the serotonin transporter promoter region polymorphism
Elizabeth P Hayden1, Lea R Dougherty, Bryan Maloney
1University of Western Ontario, Department of Psychology, London, Ontario Canada N6A 5C2. ehayden@uwo.ca
Background:
Serotonin transporter promoter (5-HTTLPR) genotype appears to increase risk for depression in the context of stressful life events. However, the effects of this genotype on measures of stress sensitivity are poorly understood. Therefore, this study examined whether 5-HTTLPR genotype was associated with negative information processing biases in early childhood.
Method:
Thirty-nine unselected seven-year-old children completed a negative mood induction procedure and a Self-Referent Encoding Task designed to measure positive and negative schematic processing. Children were also genotyped for the 5-HTTLPR gene.
Results:
Children who were homozygous for the short allele of the 5-HTTLPR gene showed greater negative schematic processing following a negative mood prime than those with other genotypes. 5-HTTLPR genotype was not significantly associated with positive schematic processing.
Limitations:
The sample size for this study was small. We did not analyze more recently reported variants of the 5-HTTLPR long alleles.
Conclusions:
5-HTTLPR genotype is associated with negative information processing styles following a negative mood prime in a non-clinical sample of young children. Such cognitive styles are thought to be activated in response to stressful life events, leading to depressive symptoms; thus, cognitive styles may index the "stress-sensitivity" conferred by this genotype.
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