Psychological stress has been associated with higher levels of inflammation and the risks of many physical disorders including heart diseases. For example, chronic stress responses may cause a variety of skin disorders including allergic inflammation, skin cancer, and psoriasis. Inflammatory processes are the common complications of a wide range of diseases including diabetes and cancer.
The emerging field of psychoneuroimmunology (PNI) focuses on the interactions among the immune system, the central nervous system (CNS), and behavior. An integrative approach is needed to combine immunology and neuroscience to have a holistic view of the associations among stress, inflammation, and chronic diseases. A universal framework combining PNI and ecological immunology would allow for a better insight into the behavior-neuro-endocrine-immune interactions in an ecological and evolutionary way (see Chapters 1).
The associations between social and genetic factors may affect complex behavioral and disease phenotypes. Both genetic and environmental factors can influence human personality. Gene-environment interactions may affect neural processing and play a critical role in individual differences in behaviors and disease susceptibility (see Chapters 1, 2, 4). The identification of these factors can help with the development of strategies for more targeted care in personalized medicine.
Specifically, individual coping strategies may affect stress responses and inflammatory processes, leading to different health results in different people (see Chapter 2). The behavioral disorders caused by psychological stress may disturb homeostasis and influence the immune functions. On the other hand, the dysregulation of the cytokine signaling in the immune activities may lead to psychological problems such as anxiety, depression, and cognitive dysfunctions (see Chapter 3).
Depression has been associated with higher levels of inflammatory activities. Inflammation can be enhanced by stress and depression, such as in the condition of troubled relationships. It is necessary to examine the influences of depression on the morbidity and mortality in chronic disorders including cardiovascular diseases, cancer, obesity, diabetes, asthma, and arthritis (see Chapter 3).
In addition, bereavement may have influences on the immune functions by affecting gene transcriptions in the immune cells. Various mental and emotional reactions such as grief and bereavement have been linked to altered neuroendocrine activations and sleep disorders (see Chapter 4).
Sleep disturbance has a significant role in the development of both mental and physical diseases, including depression, infectious diseases, cardiovascular diseases, and cancer. The interactions between sleep and health in both psychological and physical aspects may have significant effects on inflammation. Studies on the psychosocial and neurobiological processes underlying the pathophysiology of insomnia may contribute to the integrative interventions of various disorders (see Chapter 5).
Furthermore, PNI studies have indicated that bipolar disorder (BD) is associated with a chronic pro-inflammatory condition. Autism spectrum disorders (ASD) are related to the malfunctions of multiple biological pathways, especially the cytokines of the immune system. In the pathophysiology of schizophrenia, activated peripheral and central inflammatory responses play critical roles. Environmental and genetic factors may be involved in these inflammatory processes and the progression of schizophrenia (see Chapter 6).
Moreover, individual differences in perceptual factors such as predictability and neuronal plasticity may contribute to the different responses to stress and trauma. Traumatic Brain Injury (TBI) starts with a series of neuro-modulatory damages involving physical and psychological alterations, especially neuroendocrine dysfunctions. Impulsive behaviors are the important features of the disorders including borderline personality disorder (BPD) and attention-deficit/hyperactivity disorder (ADHD). In addition to conventional therapies, immunotherapy may provide promising interventions for the problems such as nicotine addiction and stimulant use disorders (see Chapter 6).
In summary, the interactions between genetic variabilities and environmental stressors may result in higher levels of inflammatory biomarkers among genetically susceptible adults. From the perspective of systems biology, the dysfunctions of the hypothalamic-pituitary-adrenal (HPA) axis have been related to depression, anxiety, and depression-associated diseases (see Chapters 1 and 7). The studies of the associations among diurnal cortisol rhythms, altered HPA activities, life stress, and depression may be useful for the discovery and development of better therapeutic strategies.