Because children are almost invariably reared in a network of intimate relationships that, if not a natural or adopted family, has some other social context (usually institutional) in the first three or four years, the individual is imprinted with the norm of being accompanied. Someone – whether parents, siblings, age cohorts, friends, relatives, social workers – is in daily contact with the child. This position of security may change gradually, for instance, if childhood companions grow away from each other, or suddenly, perhaps by a change in location or situation or by a death.
Lonely children are often 'unpopular' children, meaning children who are not readily accepted by their peers and who do not make friends. Children may be isolated or rejected because they are unaware of the modes of behaviour which contribute to peer acceptance, they lack insight into the adverse effects of their behaviour on peer relations and they lack the social skills necessary for making friends. The lonely child lacks a feeling of security and belonging.
Major categories of isolated children are those with impairments; those who are new in a community; those whose parents are excessively conspicuous due to position, behaviour, history or unusual circumstances; those in linguistic, racial, ethnic or religious minorities; and children who are categorized, less scientifically, as introverted, intellectual or awkward. In the developmental cycle, the onset of puberty may create behavioural and psychological manifestations leading to separation from former friends. The adolescent may be the individual who feels loneliness most keenly. In some cases this may lead to leaving home prematurely under conditions as varied as premature marriage, military enlistment or running away.