People can experience loneliness for many reasons and many life events are associated with it, like the lack of friendship relations during childhood and adolescence, or the physical absence of meaningful people around a person are a few causes for loneliness. At the same time, loneliness may be a symptom of another social or psychological problem, such as chronic depression.
Many people experience loneliness for the first time when they are left alone as infants. It is also a very common, though normally temporary, consequence of a breakup, divorce, or loss of any important long-term relationship. In these cases, it may stem both from the loss of a specific person and from the withdrawal from social circles caused by the event or the associated sadness.