Loneliness was associated with higher rates of depression, anxiety, and suicide.
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.
Some research suggests that loneliness is associated with an increased risk of certain mental health problems, including depression, anxiety, low self-esteem, sleep problems and increased stress.
"Lacking encouragement from family or friends, those who are lonely may slide into unhealthy habits," Valtorta says. "In addition, loneliness has been found to raise levels of stress, impede sleep and, in turn, harm the body. Loneliness can also augment depression or anxiety."
Research suggests that several risk factors may increase a person's risk of becoming isolated or lonely. These include mental or physical health conditions, low education or income, and social factors (eg, unmarried, living alone).
"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," says Katherine Peters, MD, PhD, FAAN, associate professor of neurology and neurosurgery at Duke University.
Three profiles of people at particular risk from loneliness were identified: Widowed older homeowners living alone with long-term health conditions. Unmarried, middle-agers with long-term health conditions. Younger renters with little trust and sense of belonging to their area.
Loneliness is associated with ill-health
Yet, loneliness also impacts cognition and has been shown in longitudinal studies to predict cognitive decline (Shankar, Hamer, McMunn & Steptoe, 2013) and risk for Alzheimer's disease (Wilson et al., 2007).
Loneliness is associated with increased mortality and a higher risk of some cardiovascular, metabolic and neurological disorders. Co-ordinated approaches at the individual, community and society levels are needed to reduce loneliness.
Social isolation is often linked to severe health concerns such as cancer, inflammation, hypertension and other diseases. In addition, social isolation can cause anxiety, low self-esteem and depression. People who don't socialize may struggle with reduced resilience and have difficulties coping with stress.
What causes loneliness? There is not one single cause of loneliness. Loneliness can often be a result of life changes or circumstances that include living alone, changing your living arrangements, having financial problems, or death of a loved one.
Biologists have shown that feelings of loneliness trigger the release of stress hormones that in turn are associated with higher blood pressure, decreased resistance to infection and increased risk of cardiovascular disease and cancer.
Your nervous system goes into fight-or-flight mode, making it harder to sleep. When you're lonely, research shows that your brain can produce an excess of norepinephrine, a hormone that's a crucial “signal during the fight or flight response.” Loneliness can feel, to our social selves, like dire straits.
“When you're experiencing loneliness, your levels of cortisol, a stress hormone, go up,” she says. “Cortisol can impair cognitive performance, compromise the immune system, and increase your risk for vascular problems, inflammation and heart disease.”
When someone feels lonely they are more likely to try to distract themselves with the other things in their lives. So if your colleague is always talking about their stamp collection, or always flying away on exotic solo city breaks rather than spending weekends at home, they might be feeling alone.
Loneliness is toxic
Loneliness has clear consequences for mental health, aggravating anxiety, depression, and stress-related symptoms. Additionally, it sabotages our physical health. According to two leading researchers, loneliness triggers an inflammatory response and threatens our immune system.
Definition of Loneliness
Loneliness causes people to feel empty, alone, and unwanted. People who are lonely often crave human contact, but their state of mind makes it more difficult to form connections with other people. Loneliness, according to many experts, is not necessarily about being alone.
Most notably, researchers found that loneliness rates peak among people in their 20s, and reach their lowest point among those in their 60s. Many people also experience a spike in lonely feelings around their mid-40s. These findings are as confounding as they are surprising, at least initially.
Some of the most common causes of loneliness include: Social Anxiety, Isolation, Difficulty with Assertiveness, and Poor Self-awareness. Common types or forms of loneliness include: Lack of Physical Connection, Lack of Common Interests, Lack of Shared Values, Lack of Emotional Intimacy, and Lack of Self-Intimacy.
Research has shown that chronic social isolation increases the risk of mental health issues like depression, anxiety and substance abuse, as well as chronic conditions like high blood pressure, heart disease and diabetes. It also raises the risk of dementia in older adults.