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 BDNFval66met 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 serotonin transporter-linked polymorphic region (5-HTTLPR) of the serotonin transporter gene (SLC6A4) S allele is linked to pathogenesis of depression and slower response to selective serotonin reuptake inhibitors (SSRIs); depression and SSRIs are independently associated with bone loss.
Exposure of an organism to chronic psychosocial stress may affect brain-derived neurotrophic factor (BDNF) expression that has been implicated in the etiology of psychiatric disorders, such as depression.
Further, we employ a design that addresses specific limitations of many prior studies that have examined the 5-HTTLPR × SLE relation, by: (a) using a within-person repeated-measures design to address fluctuations that occur within individuals over time, increase power for detecting G × E, and address GE correlation; (b) studying reports of exogenous stressful events (those unlikely to be caused by depression) to help rule out reverse causation and negativity bias, and in order to assess stressors that are more etiologically relevant to depressive symptomatology in older adults.
Serotonin (5-hydroxytryptamine, 5-HT) and brain-derived neurotrophic factor (BDNF) are two signaling molecules that have important regulatory roles in the development and plasticity of neural circuits that are known to be altered in depression.