social isolation 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. not to be confused with social distancing, emotional isolation, or recluse. 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. the magnitude of risk associated with social isolation is comparable with that of cigarette smoking and other major biomedical and psychosocial risk factors. however, our understanding of how and why social isolation is risky for health – or conversely – how and why social ties and relationships are protective of health, still remains quite limited. james s. house, psychosomatic medicine, 2001, issue 2, volume 63, pages 273–274 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: staying home for an indefinite period of time due to lack of access to social situations rather than a desire to be alone; both not contacting, and not being contacted by, any acquaintances, even peripherally; for example, never being called by anybody on the telephone and never having anyone visit one's residence; a lack of meaningful, extended relationships, and especially close intimacy (both emotional and physical). contributing factors the following risk factors contribute to reasons why individuals distance themselves from society. aging – once a person reaches an age where problems such as cognitive impairments and disabilities arise, they are unable to go out and socialize. health and disabilities – people may be embarrassed by their disabilities or health problems, such that they have a tendency to isolate themselves to avoid social interaction out of fear that they would be judged or stigmatized. sometimes, rather than embarrassment, the disability itself and a person's lack of a support network can be the cause of social isolation. autism – autistic and allistic (non-autistic) people communicate very differently, leading to a mutual friction when they try talking to each other. as autistic people are in a steep minority, often unable to find peers who communicate the same way they do, they are often ostracised by the majority, who mistake their direct, semantic communication style for them being purposefully arrogant, brash, and obtuse. hearing loss – hearing loss can cause communication impairment, which can lead to social isolation particularly in older adults. 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. living alone – a 2015 study by the national center for family & marriage research found 13 percent of adults in the united states were living alone, up from 12 percent in 1990. the rate of living alone for people under 45 has not changed, but the rate for americans aged 45 – 65 has increased over the past 25 years. people over the age of 65 are living alone less often. isolation may be imposed by an abusive spouse. rural isolation - in rural areas, factors such as living far apart from one another, rural flight, a negligible amount of public spaces and entertainment, and lack of access to mental health-related resources all contribute to isolation. limited access to broadband internet and cellular activity also make it harder for those experiencing isolation to connect online or reach people. unemployment – this can begin if someone is fired, dismissed, or released from a job or workplace, or leaves one of their own accords. if the person struggles or is unable to find a new job for a long period of time (i.e. months or years) the