Can the psychology of a middle-aged person alter their immune health? I have read about the different types of linkage between nervous system and immune system.
Can someone outline the general facts about what is understood about this?
I'm not sure what you mean by psychology exactly, but assuming you are referring to a persons mental state there is a known link between stress and immunity. This link occurs through neuro-endocrine pathways. The central nervous system and endocrine (hormonal) systems are linked through the hypothalamus, a key controller of hormone release in the central nervous system. In a state of stress our central nervous system reacts by increasing the release of hormones such as the steroid cortisol and catacholamines such as adrenaline (a.k.a epinephrine in USA).
We know that steroids have an effect of dampening down the immune system (in fact steroids are often used for this intentionally in the case of autoimmune conditions for example). Thus based on this we have a scenario where stress can lead to increase in cortisol (and other hormones) which in turn can have an effect on your immunity. The effect to which this impacts on your life is then further dependent on your psychology and social support.
More generally, the links between illness and psychology are integrated together in what is called the biopsychosocial model of illness. I suggest you look this up to gain a more in depth understanding of this complicated issue.
Yes. It's called Psychoneuroimmunology Ziemssen & Kern 2007:
There is evidence for rich neural connections with lymphoid tissue Steinman et al.(2004). Receptors for various neurotrans mitters beyond acetylcholine and norepinephrine are also present on lymphocytes. Whereas the parasympa thetic neurotransmitter acetylcholine potently modu lates several classical immune reactions via the vagus nerve, the sympathetic nervous system can alter the TH1/TH2 balance through stimulation of the beta- adrenergic receptor for example Elenkov et al. 2000
In general: Personal well being (PWB) makes you healthier, Psychological Ill-Being (PIB) makes you unhealthier, here are some snippets of a review (Abdurachman & Herawati 2018):
Coping mechanisms improved the outcome of AIDS patients
Religious coping and social support as an effort towards PWB showed to boost the immune responses in people living with HIV/AIDS (Dalmida et al, 2013). They used CD4 + cell count to prove their findings. Then, the effort to PWB via religious coping was definitely associated with reduced psychological distress, increased health-related quality of life (HRQoL), and better medication adherence (8-item Morisky Medication Adherence). Dalmida et al, 2013
Weeks of Playing music shifts your immune system from inflammatory to anti-inflammatory
Researchers found an increased immune response through various indicators obtained through saliva samples such as: cortisol, cytokines and interleukin (IL) -4, IL-6, IL-17, tumor necrosis factor-alpha (TNF-α), and monocyte protein chemoattractant (MCP) -1 (Fancourt et al., 2016b). This study shows the psychological benefits of group drumming and shows the underlying biological effects, supporting the therapeutic potential for mental health.
One might think that this all comes down to happy = no stress. Since there is tons of research out there proving that
STRESS makes you unhealthy
Spinorial already mentioned the stress hormone cortisol and its effect on dampening the immune system. Here I wanna provide some more facts that I took from this review (Yaribeygi et al. 2017 doi: 10.17179/excli2017-480):
Stress makes your immune system to attack your guts
Stress can re-activate previous inflammation of your gastrointestinal system. It can get worse:
As a result, there is an increase in the permeability of cells and recruitment of T lymphocytes. Lymphocyte aggregation leads to the production of inflammatory markers, activates key pathways in the hypothalamus, and results in negative feedback due to CRH secretion, which ultimately results in the appearance of [gastrointestinal system] inflammatory diseases. [...] It has been suggested that even childhood stress can lead to these diseases in adulthood (Schwartz and Schwartz, 1983, found in Yaribeygi et al. 2017).
Stress stops the immune system from killing cancer
stress can decrease the activity of cytotoxic T lymphocytes and natural killer cells and lead to growth of malignant cells, genetic instability, and tumor expansion (Reiche et al. 2004 found in Yaribeygi et al. 2017)
Stress slowly kills you by damaging your blood vessels and heart
Most human deaths can be related to accumulated damages to the cardiovascular system (So stop worrying about immune system). The mechanism behind stress killing you seems to be fairly simple:
Stress can stimulate the autonomic sympathetic nervous system to increase vasoconstriction, which can mediate an increase in blood pressure, an increase in blood lipids, disorders in blood clotting, vascular changes, atherogenesis; all, of which, can cause cardiac arrhythmias and subsequent myocardial infarction
Stress Shortens Telomeres
I came across a paper when I was answering a question about telomeres. Mental stress shortens telomeres (Epel et al 2004). To understand how short telomeres affect the immune system, aging and health see Does Telomere length shortening cause our cells to stop functioning properly?