Mrs. X repeatedly stated when I was interviewing her how she was grateful and lucky for the support she has at home whilst still living on her own and having independence. She said about her neighbors who check in on her, a son and daughter in law who lived nearby and who she sees regularly, as well as two daughters who ring her often. This made me think about patients who may not be as ‘lucky’, who live alone, may be socially isolated, lonely and what effect this could have on their health. There is a difference between loneliness and social isolation and they don’t always go hand in hand. For example, some people are constantly surrounded by people and so are not socially isolated but still feel lonely, whilst others (like Mrs. X) live on their own but do not feel lonely at all. Loneliness can therefore be described as perceived social isolation rather than objective social isolation. Although they are notably different, both social isolation and loneliness have been linked by research to an increased risk of several conditions, both physical and mental. In this essay, when I refer to social isolation, I will be assuming that the individual is also experiencing loneliness. I think this is a particularly important subject to explore, especially coming out of a years’ worth of lockdowns – where many people will have experienced very real social isolation with no way to socialize due to strict Covid-19 rules. This will have been especially more prominent is the elderly population, like Mrs. X who had to shield due to their age and the risk of Covid-19 to them.
Studies have suggested that loneliness increases the risk of early mortality by 26-32%, which is comparable to the risk of more known dangers like obesity and smoking. The physiology behind the physical effects of loneliness and social isolation are not fully understood but it is known that they are chronic forms of stress and so evidence has shown that as a result they activate the hypothalamic-pituitary-adrenal (HPA) axis. The HPA axis releases cortisol. Cortisol is commonly known as the bodies ‘stress hormone’. It’s the main glucocorticoid released from the adrenals, specifically the zona fasciculata layer. Glucocorticoid receptors are in the majority of tissues within the body and so cortisol level changes can have a wide range of effects. The chronic stress caused by loneliness and social isolation has also been seen to activate the sympathetic nervous system which activates fight or flight responses however the research around this is less consistent than activation of the HPA axis.
High-Blood Pressure and Cardiovascular Disease
Research has suggested that there is a 29% increased risk of heart attack or angina and a 32% increased risk of stroke in people with poor social relationships, this is a shocking statistic and so I will explore the cardiovascular effects of being lonely below.
Hypertension is a condition where blood vessels have a persistently raised pressure. It is a serious condition which doesn’t present normally with any symptoms but can increase the risk of heart, brain, kidney and other diseases. The main cause of increased blood pressure is an increased total peripheral resistance, studies have shown in young adults there is research showing an increased total peripheral resistance in those who are lonely over non-lonely individuals of the same age. Results from studies also show the association between hypertension and loneliness in older and middle-aged individuals. Loneliness may affect an individual’s blood pressure when feeling isolated as, like said earlier, it’s a form of stress which activates the HPA axis which will increase cortisol secretion which increases blood pressure.
As well as causing hypertension, there’s been a lot of evidence from animal studies which suggests that social isolation accelerates atherosclerosis. It’s suggestive that the molecular mechanisms behind this include the sympathetic nervous system over activation and physical inactivity, as well as enhanced vascular inflammation and oxidative stress. This means that loneliness activates the sympathetic nervous system without need. The sympathetic nervous system is for the fight or flight response. Atherosclerosis is a disease where a plaque, made up of fat, cholesterol, calcium builds up in arteries. This plaque develops over time and leads to narrowing and hardening of arteries. It is a major risk factor for heart attacks and strokes, as well as other diseases such as chronic kidney disease, peripheral artery disease, and ischemic heart disease, therefore loneliness may contribute to all these diseases.
As well as cardiovascular disease, because loneliness and social isolation can lead to chronic HPA axis stress response – releasing chronically high levels of cortisol – this also negatively affects your immune system. It’s been shown in a study which looked at gene expression, that participants of the study who were lonely had leukocytes with increased expression of genes involved in inflammation as well as lowered expression of genes involved in antiviral responses. Another study showed using three markers of inflammation (CRP, plasma fibrinogen and ferritin) showing that loneliness was associated with an increase in these markers of inflammation. This shows that lonely people may have decreased immunity and increased inflammation which could predispose them to various types of cancer underlying infections and inflammatory responses are linked to 15-20% of all deaths from cancer worldwide.
Dementia is an umbrella term for a variety of different conditions which cause loss of memory, language, problem-solving skills, as well as other thinking abilities which interfere with the activities of daily life. Research has shown that loneliness is associated with a 26% increased risk of dementia and a 105% risk of mild cognitive impairment (a precursor to dementia). The theory behind why is poorly understood but researchers believe that lonely individuals may engage in less healthy behaviors, such as decreased exercise, poor diet, and drug and alcohol abuse. Loneliness is also associated with depression, a risk factor for Alzheimer’s (the most common form of dementia). People who are socially isolated also lack stimulation cognitively though socializing with others, which is not ideal when looking at the risk for dementia as increased cognitive activity reduces risk of it. There’s evidence that people who experience perceived social isolation also have higher levels of amyloid and tau build up in their brain. These build ups are directly associated with the development of Alzheimer’s disease.
The effects of social isolation on mental health have a more well-known risk. Most people know about the association between loneliness and depression, anxiety and suicide risk. From the US there’s evidence on how extreme isolation can affect mental health through looking at prisoners who spend weeks or months at a time in isolation. They are in small, windowless cells. This deprives the prisoners of sensory stimuli and all social interaction. Information gained from these individuals shows that this kind of isolation leads to difficulty with memory, obsessive thinking, difficulty thinking, hallucinations and other psychotic symptoms. It was also found to have an increased risk of long-term mental health risks as well as a higher risk of suicide. This is a very extreme representation of social isolation but shows an association between isolation and mental health decline none the less. Loneliness has been associated with personality disorders and psychoses, suicide, impaired cognitive performance and decline, and increases in depressive symptoms.
Depression is believed to be multifactorial and not one thing causes it. Things that play a role in the development of it are: biological factors, psychological factors, individual circumstances and particular life events. Loneliness can contribute to depression as it translates to feelings of social isolation or feeling unsatisfied with interpersonal relationships and this can all contribute to feelings of depression.
Loneliness and disrupted sleep also have a relationship. However, it is also unclear which causes what. Some studies suggest that lack of good quality sleep can result in social isolation and loneliness. Whereas other studies point towards loneliness causing sleepless nights. This also overlaps with depression causing lack of sleep. All three (loneliness, depression and lack of sleep) may therefore cause a vicious cycle between them.
Secondary Effects on Health
As well as directly affecting health, loneliness can affect health indirectly as well. This is due to people turning to addictive habits to help avoid the problem, like smoking, alcohol abuse and drug abuse. These addictions in terms leads onto a whole host of different conditions and diseases.
Loneliness was already a major issue recognized in the United Kingdom, even previous to Covid-19, which many people faced.
In conclusion, loneliness and social isolation has been associated with increased risk of death, cardiovascular disease and stroke, hypertension, impaired immunity, cognitive decline and depression. During writing this essay I was shocked to find out all the adverse effects of loneliness and that they were comparable with known health risk factors like obesity and smoking. These more well-known factors have major public health campaigns to try and avoid them. Coming out of a year of lockdown’s with Covid-19 I think now is a really important time to put a lot of emphasize on making people aware of the health risks associated with loneliness and isolation, to try and battle it.