Final answer:
The genetic factors for depression include polymorphisms in neurotransmitter system genes and genes regulating the stress response and inflammation. Genetic predispositions combined with environmental stressors contribute to depression risk, with cytokines playing a notable role in the disorder's etiology.
Step-by-step explanation:
The genetic factors for Liona's depression, or its etiology, include complex interactions between genetic predispositions and environmental stressors. Research has shown that polymorphisms in genes such as the serotonin transporter (5-HTT), corticotropin-releasing hormone receptor 1 (CRHR1), and cytokines are associated with an increased risk for developing depression. For instance, a study by Licinio et al. (2004) found an association between a CRHR1 haplotype and the response to antidepressant treatment among Mexican Americans, suggesting a genetic influence on drug efficacy.
Further, the inflammatory response, regulated by cytokines, has been linked to depression's neurobiological changes. The upregulation of pro-inflammatory cytokines and immune system factors, such as interleukins and tumor necrosis factors, might contribute to the onset of depressive symptoms. Genes involved in the inflammatory response could therefore be crucial factors in depression's etiology. According to Moffitt et al. (2007), early-life stress and genetic variations jointly contribute to the risk of developing depression. In summary, depression is a multifactorial disorder with genetic components that affect neurotransmitter systems, stress response pathways, and inflammation.