At any age, loneliness can have detrimental effects on overall health. It's a major risk factor for depression and various forms of anxiety as well as cognitive deficits. "Loneliness can change the neurochemistry of the brain, turning off the dopamine neurons, which trigger the reward response, and causing some degeneration in the brain when the reward response is not activated.

Chronic loneliness increases the risk of heart disease and diabetes. It also causes mental health problems, such as anxiety, depression, low self-esteem, sleep problems and increased stress.

Loneliness increases the risk of developing dementia.

Article Association of Loneliness With 10-Year Dementia Risk and Ear...

Article Loneliness Increases the Risk of All-Cause Dementia and Alzh...

Loneliness and social isolation increases risk of heart disease by 27% for older women.

https://jamanetwork.com/journals/jamanetworkopen/fullarticle/2788582

Loneliness alters immune system of the body.

Article Myeloid differentiation architecture of leukocyte transcript...

Loneliness is associated with cognitive decline.

Article Are loneliness and social isolation associated with cognitive decline?

Loneliness is also linked to obesity.

Article Overweight and Lonely? A Representative Study on Loneliness ...

Research has linked social isolation and loneliness to higher risks for a variety of physical and mental conditions: high blood pressure, heart disease, obesity, a weakened immune system, anxiety, depression, cognitive decline, Alzheimer's disease, and even death.

https://www.nia.nih.gov/news/social-isolation-loneliness-older-people-pose-health-risks

Loneliness can modify the neurochemistry of the brain, turning off the dopamine neurons that trigger the reward response and causing some degeneration in the brain.

https://www.brainandlife.org/articles/how-loneliness-affects-health

Also, kindly check:

Loneliness and Social Isolation Linked to Serious Health Conditions:

https://www.cdc.gov/aging/publications/features/lonely-older-adults.html

Dear Seyi Festus Olatoyinbo . It leads to higher risks for a variety of physical and mental conditions: high blood pressure, heart disease, obesity, a weakened immune system, anxiety, depression, cognitive decline, Alzheimer's disease, and even death. See the link: https://www.nia.nih.gov/news/social-isolation-loneliness-older-people-pose-health-risks#:~:text=Research%20has%20linked%20social%20isolation,Alzheimer's%20disease%2C%20and%20even%20death.

Kindly see also the following useful RG links: Article The complexity of loneliness

Article Loneliness Matters: A Theoretical and Empirical Review of Co...

https://link.springer.com/article/10.1007/s40656-021-00372-z#:~:text=A%20review%20article%20notes%20that,(Hawkley%20and%20Cacioppo%202010).

Also check please the following useful RG links: Article Health risks associated with social isolation in general and...

Article Social isolation in Covid-19: The impact of loneliness

The following RG links are also very useful: Article Loneliness correlates and associations with health variables...

Article Problems of Loneliness and Its Impact on Health and Well- Being

Article Cumulative effect of loneliness and social isolation on heal...

Visit also the following useful RG links: Article Suffering from Loneliness Indicates Significant Mortality Ri...

https://www.globalhealthprojects.org/loneliness/

https://tilda.tcd.ie/publications/reports/pdf/Report_Loneliness.pdf

The longer you experience feelings of loneliness, the more prone you are to hypertension, high cholesterol, and obesity. And single women also have a higher incidence of coronary heart disease (according to my research).

As a psychogenic factor, loneliness affects the human psyche and causes acute emotional reactions (including painful experiences, anxiety, depression, depersonalization, hallucinations), changes in consciousness and self-awareness, individual and personal characteristics of a person.

In lonely people, the genes responsible for the body's inflammatory response are much more active. And that's pretty dangerous. Yes, inflammation is necessary for the body to cope with injury. But if inflammatory processes occur constantly, this creates an excellent environment for the development of atherosclerosis, cardiovascular and neurodegenerative diseases, as well as metastatic cancer. Here is one explanation why single people are more prone to such diseases.

At the same time, the activity of a group of genes responsible for fighting viral infections is suppressed. These genes are responsible for the production of special proteins - type 1 interferons, which prevent the reproduction of viruses in the body.

Researchers have found that low levels of loneliness are associated with marriage, higher incomes, and higher educational status. High levels of loneliness are associated with physical health symptoms, living alone, small social networks, and low-quality social relationships.

I think the feeling of Loneliness, is the condition of feeling negative regarding your surroundings including family and friends, ultimately goes to depression

@ Prof. Aref Wazwaz Thanks for your invaluable contributions, as usual. My profound appreciation Sir.

@ Dr. Sergey Viktorovich Pushkin Thanks for your insightful contribution. It is highly appreciated!!!

Suraj Kapoor Thanks for your valuable response. Best regards!!!

@ Dr. Narimen Yousfi

@ Dr. Manal Hadi Kanaan Thanks for your invaluable contributions. Highly appreciated!!!

@ Dr. Arvind Singh Your insightful responses are well appreciated, as usual. Many thanks!!!

Aijaz Panhwar Your thoughtful comment is well appreciated. Many thanks!!!

You are most welcome dear Seyi Festus Olatoyinbo .

Wish you the best always

Effect of loneliness on human health is obviously devastating.Varied psychosomatic perturbations observed are seemingly more intense in late age due to diminished endurance.It is surprising to note that loneliness adversely affects an individual even when he/she is not literally alone. The very feel of being ignored at any point of time makes one sad, lonely and hapless. Extent of loss could be thought linked with episodes of insults and assaults to brain. Damage control largely depends on neurophysiologic responsiveness and reversal of conditions causing loneliness and anxiety. Unconditional familial care is sure to reduce the threat of loneliness.Let us join hands to create society for all ages leaving no room for loneliness and associated trauma.

Prof. Bhaweshwar Singh Thanks for your laudable contribution. Well appreciated!!!

Seyi Festus Olatoyinbo

Loneliness can have negative impact on COVID-19 vaccine antibody response.

https://www.sciencedirect.com/science/article/pii/S0889159122001155

Thanks!

Also, see the following RG link.

Article Associations of Social Isolation and Loneliness With Later Dementia

Arvind Singh Thanks for the article shared and useful link provided. My best regards!!!

The prolonged exposure to loneliness and social isolation are likely to increase the risk of mental health disorders such as anxiety, depression, and suicide ideation as stated in the study by Callahan, King and Halversen, 2020. you can also read Article LONELINESS AND MENTAL HEALTH AMONGST INDIANS WORKING IN ABU DHABI, UAE

Hitesh Mohan Thanks for our insightful comment. Well appreciated!!!

@ Dr. Fawaz Raad Jarullah

Depression is the major outcome of loneliness

Dr. Abhijit Mitra Thanks for your apt contribution. Cheers!!!