Social isolation
Social isolation is a state of complete or near-complete lack of contact between an individual and society. It differs from loneliness, which reflects temporary and involuntary lack of contact with other humans in the world. Social isolation can be an issue for individuals of any age, though symptoms may differ by age group. Social isolation has similar characteristics in both temporary instances and for those with a historical lifelong isolation cycle. All types of social isolation can include staying home for lengthy periods of time, having no communication with family, acquaintances or friends, and/or willfully avoiding any  contact with other humans when those opportunities do arise. Effects. True social isolation over years and decades can be a chronic condition affecting all aspects of a person's existence. Social isolation can lead to feelings of loneliness, fear of others, or negative self-esteem. Lack of consistent human contact can also cause conflict with the (peripheral) friends. The socially isolated person may occasionally talk to or cause problems with family members. In the case of mood-related isolation, the individual may isolate during a depressive episode only to 'surface' when their mood improves. The individual may attempt to justify  their reclusive or isolating behavior as enjoyable or comfortable. There can be an inner realization on the part of the individual that there is something wrong with their isolating responses which can lead to heightened anxiety. Relationships can be a struggle, as the individual may reconnect with others during a healthier mood only to return to an isolated state during a subsequent low or depressed mood. Perceived social isolation in humans. Research indicates that perceived social isolation (PSI) is a risk factor for and may contribute to “poorer overall cognitive performance and poorer executive functioning, faster cognitive decline, more negative  and depressive cognition, heightened sensitivity to social threats, and a self-protective confirmatory bias in social cognition.” PSI also contributes to accelerating the ageing process: Wilson et al. (2007) reported that, after controlling for social network size and frequency of social activity, perceived social isolation is predictive of cognitive decline and risk for Alzheimer's disease. Moreover, the social interactions of individuals who feel socially isolated are more negative and less subjectively satisfying. This contributes to a vicious cycle in which the person becomes more and more isolated. Neuroimaging studies. In the first resting state fMRI functional connectivity (FC) study  on PSI, PSI was found to be associated with increased resting-state FC between several nodes of the cingulo-opercular network, a neural network associated with tonic alertness. PSI was also associated with reduced resting-state FC between the cingulo-opercular network and the right superior frontal gyrus, suggesting diminished executive control. Cacioppo and colleagues (2009) found that lonely individuals express weaker activation of the ventral striatum in response to pleasant pictures of people than of objects, suggesting decreased reward to social stimuli. Lonely individuals also expressed greater activation of the visual cortex in response to unpleasant depictions of people  (i.e., negative facial expressions) than of objects; non-lonely individuals show greater activation of the right and left temporoparietal junction (TPJ), a region implicated in theory of mind. The authors interpreted the findings to represent that lonely individuals pay greater attention to negative social stimuli, but non-lonely individuals, to a greater degree than lonely individuals, insert themselves into the perspective of others. Moreover, Kanai et al. (2012) reported that loneliness negatively correlated with gray matter density in the left posterior temporal sulcus, an area involved in biological motion perception, mentalizing, and social perception. Overall, several neuroimaging studies in humans  on perceived social isolation have emphasized implications of the visual cortex and right-hemispheric stress-related circuits underlying difference between lonely and non-lonely individuals. A recent population-genetics study marked a 50x increase in the neuroimaging research on perceived social isolation. The investigators tested for signatures of loneliness in grey matter morphology, intrinsic functional coupling, and fiber tract microstructure. The loneliness-linked neurobiological profiles converged on a collection of brain regions known as the default mode network. This higher associative network shows more consistent loneliness associations in grey matter volume than other cortical brain networks. Lonely individuals display stronger  functional communication in the default network, and greater microstructural integrity of its fornix pathway. The findings fit with the possibility that the up-regulation of these neural circuits supports mentalizing, reminiscence and imagination to fill the social void. Social isolation in rodents. Experimental manipulations of social isolation in rats and mice (e.g., isolated rearing) are a common means of elucidating the effects of isolation on social animals in general. Researchers have proposed isolated rearing of rats as an etiologically valid model of human mental illness. Indeed, chronic social isolation in rats has been found to lead to depression-, anxiety-, and  psychosis-like behaviors as well signs of autonomic, neuroendocrine, and metabolic dysregulation. For example, a systematic review found that social isolation in rats is associated with increased expression of BDNF in the hippocampus, which is associated with increased anxiety-like symptoms. In another example, a study found that social isolation in rats is associated with increased brain-derived neurotrophic factor (BDNF) expression in the prefrontal cortex. This results in the dysregulation of neural activity which is associated with anxiety, depression, and social dysfunction. The effects of experimental manipulations of isolation in nonhuman social species has been shown to resemble the  effects of perceived isolation in humans, and include: increased tonic sympathetic tone and hypothalamic-pituitary-adrenal (HPA) activation and decreased inflammatory control, immunity, sleep salubrity, and expression of genes regulating glucocorticoid responses. However, the biological, neurological, and genetic mechanisms underlying these symptoms are poorly understood. Neurobiology. Social isolation contributes to abnormal hippocampal development via specific alterations to microtubule stability and decreased MAP-2 expression. Social isolation contributes to decreased expression of the synaptic protein synaptophysin and decreased dendritic length and dendritic spine density of pyramidal cells. The underlying molecular mechanism of these structural neuronal alterations are microtubule stabilizations, which impair the  remodeling and extension of axons and dendrites. Research by Cole and colleagues showed that perceived social isolation is associated with gene expression – specifically, the under-expression of genes bearing anti-inflammatory glucocorticoid response elements and over-expression of genes bearing response elements for pro-inflammatory NF-κB/Rel transcription factors. This finding is paralleled by decreased lymphocyte sensitivity to physiological regulation by the HPA axis in lonely individuals. This, together with evidence of increased activity of the HPA axis, suggests the development of glucocorticoid resistance in chronically lonely individuals. Social isolation can be a precipitating factor for suicidal behavior. A  large body of literature suggests that individuals who experience isolation in their lives are more vulnerable to suicide than those who have strong social ties with others. A study found social isolation to be among the most common risk factors identified by Australian men who attempt suicide. Professor Ian Hickie of the University of Sydney said that social isolation was perhaps the most important factor contributing to male suicide attempts. Hickie said there was a wealth of evidence that men had more restricted social networks than women, and that these networks were heavily work-based. A lack of social relationships  negatively impacts the development of the brain's structure. In extreme cases of social isolation, studies of young mice and monkeys have shown how the brain is strongly affected by a lack of social behaviour and relationships. In social animal species in general. In a hypothesis proposed by Cacioppo and colleagues, the isolation of a member of a social species has detrimental biological effects. In a 2009 review, Cacioppo and Hawkley noted that the health, life, and genetic legacy of members of social species are threatened when they find themselves on the social perimeter. For instance, social isolation decreases lifespan  in the fruit fly; promotes obesity and type 2 diabetes in mice; exacerbates infarct size and oedema and decreases post-stroke survival rate following experimentally induced stroke in mice; promotes activation of the sympatho-adrenomedullary response to an acute immobilisation or cold stressor in rats; delays the effects of exercise on adult neurogenesis in rats; decreases open field activity, increases basal cortisol concentrations, and decreases lymphocyte proliferation to mitogens in pigs; increases the 24-hour urinary catecholamine levels and evidence of oxidative stress in the aortic arch of rabbits; and decreases the expression of genes regulating glucocorticoid response in the  frontal cortex. Social isolation in the common starling, a highly social, flocking species of bird, has also been shown to stress the isolated birds. Background. Social isolation is both a potential cause and a symptom of emotional or psychological challenges. As a cause, the perceived inability to interact with the world and others can create an escalating pattern of these challenges. As a symptom, periods of isolation can be chronic or episodic, depending upon any cyclical changes in mood, especially in the case of clinical depression. Every day aspects of this type of deep-rooted social isolation can mean: Contributing  factors. The following risk factors contribute to reasons why individuals distance themselves from society. Social isolation can begin early in life. During this time of development, a person may become more preoccupied with feelings and thoughts of their individuality that are not easy to share with other individuals. This can result from feelings of shame, guilt, or alienation during childhood experiences. Social isolation can also coincide with developmental disabilities. Individuals with learning impairments may have trouble with social interaction. The difficulties experienced academically can greatly impact the individual's esteem and sense of self-worth. An example would be the  need to repeat a year of school. During the early childhood developmental years, the need to fit in and be accepted is paramount. Having a learning deficit can in turn lead to feelings of isolation, that they are somehow 'different' from others. Substance abuse can also be an element in isolation, whether a cause or a result. This can and many times does coincide with mood-related disorders, but also with loneliness. According to a study that was conducted by Kimmo Herttua, Pekka Martikainen, Jussi Vahtera, and Mika Kivimäki, living alone can increase rates of being socially isolated and leading  individuals to turn to the use of alcohol and other substances. The loss of a loved one can contribute to social isolation. Studies have shown that widows who keep in contact with friends or relatives have better psychological health. A study conducted by Jung-Hwa Ha and Berit Ingersoll-Dayton concluded that widows who had a lot of social contact and interactions lead to fewer depressive symptoms. During a time of loss social isolation is not beneficial to an individual's mental health. Whether new technologies such as the Internet and mobile phones exacerbate social isolation (of any origin) is  a debated topic among sociologists. With the advent of online social networking communities, there are increasing options to become involved with social activities that do not require real-world physical interaction. Chat rooms, message boards, and other types of communities can meet the needs of those who would rather be alone, yet still develop communities of online friends. Although, it has been shown that increased social media support is not equal to increased immediate social support in terms of combating depressive and anxious symptoms, thus supporting the value of quality of engaging in person social interaction over virtual social interaction . Isolation among the elderly. Social isolation impacts approximately 24% of older adults in the United States, approximately 9 million people. The elderly have a unique set of isolating dynamics that often perpetuate one another and can drive the individual into deeper isolation. Increasing frailty, possible declines in overall health, absent or uninvolved relatives or children, economic struggles can all add to the feeling of isolation. Among the elderly, childlessness can be a cause for social isolation. Whether their child is deceased or they didn't have children at all, the loneliness that comes from not having a child can cause  social isolation. Retirement, the abrupt end of daily work relationships, the death of close friends or spouses can also contribute to social isolation. In the United States, Canada, and United Kingdom, a significant sector of the elderly who are in their 80s and 90s are brought to nursing homes if they show severe signs of social isolation. Other societies such as many in Southern Europe, Eastern Europe, East Asia, and also the Caribbean and South America, do not normally share the tendency towards admission to nursing homes, preferring instead to have children and extended-family of elderly parents take care  of those elderly parents until their deaths. On the other hand, a report from Statistics Norway in 2016 stated that more than 30 percent of seniors over the age of 66 have two or fewer people to rely on should personal problems arise. Even still, nearly half of all members of senior communities are at high risk for social isolation, this is especially prevalent with seniors of a lower education and within the lower economic class and compounded with diminished availability of socializing options to these lower class individuals. There has also been an observed increase in physical gait among  members of these communities. Social isolation among older adults has been linked to an increase in disease morbidity, a higher risk of dementia, and a decrease in physical mobility along with an increase in general health concerns. Evidence of increased cognitive decline has been link to an increase in social isolation in depressed elderly women. The use of video communication/video calls has been suggested as a potential intervention to improve social isolation in seniors. However, its effectiveness is not known. Hearing loss and isolation. One contributing factor to social isolation among elderly individuals is age-related hearing loss. The  risk of hearing loss increases with age due to the non-regenerative nature of the hair cells in the ear responsible for hearing. As age increases, these hair cells will continue to be irreversibly damaged therefore causing hearing loss. Hearing loss, particularly in older adults, is associated with the inability to effectively communicate, which can lead to social isolation. Hearing loss can also make it difficult to maintain interpersonal relationships, which can result in social isolation. Hearing loss and loneliness have also shown associations. One Dutch study demonstrated a seven percent increase in odds of developing loneliness for each one  decibel drop in sound perception in adults under 70 years old. Isolation and health and mortality. Social isolation and loneliness in older adults is associated with an increased risk for poor mental and physical health and increased mortality. There is an increased risk for early mortality in individuals experiencing social isolation compared to those who are not socially isolated. Studies have found social isolation is associated with increased risk in physical health conditions including high blood pressure, high cholesterol, elevated stress hormones, and weakened immune systems. Research also suggests that social isolation and mortality in the elderly share a common  link to chronic inflammation with some differences between men and women. Social isolation has also been found to be associated with poor mental health including increased risk for depression, cognitive decline, anxiety, and substance use. Social isolation in elderly individuals is also associated with an increased risk for dementia. Isolation among children and teens. Middle school is a time when youth tend to be sensitive to social challenges and their self-esteem can be fragile. During this vulnerable time in development, supporting students' sense of belonging at school is of critical importance. Existing research finds that adolescents' development of a  sense of belonging is an important factor in adolescence for creating social and emotional well-being and academic success. Studies have found that friendship-related loneliness is more explanatory for depressive symptoms among adolescents than parent-related loneliness. One possible explanation is that friends are the preferred source of social support during adolescence. Scientists have long known that loneliness in adults can predispose depressive symptoms later in life. Lately, scientists have also seen that lonely children are more susceptible to depressive symptoms in youth. In one study, researchers conclude that prevention of loneliness in childhood may be a protective factor  against depression in adulthood. Socially isolated children tend to have lower subsequent educational attainment, be part of a less advantaged social class in adulthood, and are more likely to be psychologically distressed in adulthood. By receiving social assistance, studies show that children can cope more easily with high levels of stress. It is also shown that social support is strongly associated with feelings of mastery and the ability to deal with stressful situations, as well as strongly associated with increased quality of life.