Loneliness can be described as a feeling, normally unpleasant, when a person experiences a strong sense of emptiness and solitude that results from having inadequate levels of interpersonal relationships. Loneliness can also be described as a psychological mechanism that the brain uses when the individual has reached a level of too much isolation and is used as a motivation mechanism to force that person to find new social connections.
Chronic loneliness can become a serious and life-threatening condition for sufferers. It has been scientifically linked with an increased risk of cancer, stroke and cardiovascular disease, especially for those who hide their symptoms from the outside world. Not surprisingly, loneliness is commonly linked with feelings of depression and can therefore be one of the major risk factors for suicide. This has been described by Emile Durkheim as "egoistic" suicide. People who suffer from loneliness may also have poor sleep quality. Loneliness can also be a factor in substance abuse or alcoholism. Children who are lonely often exhibit antisocial or self-destructive behavior and loneliness can also negatively impact their progress at school.
Loneliness seems to be a much more prevalent phenomenon today than in the past. One of the reasons is that until the mid-20th century, families were larger and more stable, and therefore fewer people were living by themselves. In the United States, for example, in the year 1900 only 5% of households were single-person households. By 2010, this number had increased to 27 percent of all households. The Internet has also increased feelings of social isolation, with more people able to go on their computer to try and find people to write to, but still unable to form the real human connections people need in order to prevent loneliness.
Loneliness is frequently experienced during childhood or adolescence generally as a result of a lack of friendships in school. In later life, loneliness can be a sign of a psychological or social problem, for instance chronic depression. It can be experienced as one of the consequences of a divorce or the termination of another form of long-term relationships – though this is normally only temporary, as loneliness can be a natural consequence of the sadness and subsequent withdrawal from the social arena while the grieving process is completed. Loneliness is also normally experienced at a time of mourning and one can feel the emotion of loneliness even while in the presence of other people. Other times that loneliness can be experienced are after the birth of a child, which is sometimes experienced as part of postpartum depression, or following any socially disruptive event such as moving to a different location, also known as homesickness. Feelings of loneliness can also follow marriage, which socially is a time of great change. Even within marriage, loneliness is possible, though mainly if the relationship is dysfunctional. In these situations, the person experiencing loneliness can also be feeling anger or resentment.
Fortunately, there are many ways to address loneliness. One of the main treatments is therapy, during the course of which the therapist would try to understand where these feelings come from and to reverse the negative thoughts, attitudes and feelings that result from the root cause. Some doctors may also suggest group therapy as an alternative to individual sessions so that people who are feeling lonely can form their own social support network. Doctors may also try prescribing anti-depressants to sufferers, in conjunction with their talk therapy, as well as alternative therapies such as exercise, dieting or acupuncture. Other treatments for loneliness may include pet therapy, as there is positive anecdotal evidence that animals can help people feel less alone.
It is also important to note that enforced loneliness and isolation has been used as a punitive punishment method throughout all of history.