Behavioral Medical Epigenetics

Emerging evidence suggests that early-life experiences and exposure to environmental factors are strong determinants of behavior. One of the most studied and well-characterized environmental factors is stress. Exposure to stress and its primary agent cortisol is a strong risk factor for many behavioral disorders. Studies show that stress and cortisol can influence gene function through epigenetic mechanisms, which may lead to persistent changes in behavior.In this chapter, we explain how stress and our perception of the stressor activate our hypothalamic-pituitary-adrenal (HPA) axis and how exposure to chronic stress influences behaviors such as mood and addiction to drugs. Specifically, we will cover how chronic stress impacts the HPA axis itself and genes that are critical for brain function, especially those that regulate the activity of neurotransmitters. Together, evidence suggests that stress exposure affects multiple neurotransmitter systems, and behavioral disorders likely arise from a combination of deficiencies in multiple systems.