Loneliness is an emotional response by an individual to isolation, lack of companionship and lack of social or emotional connection not due to choice. Thus one can be lonely even in a crowd because of the absence of a close person. Someone can decide to remain isolated but not lonely; that is by choice.
Lonely persons have no one to spend free time with or confide in or discuss important matters with.
Common causes include: Mental abuse, Inability to fit in, Heart break, Death, Divorce, Social media, Age (old age), Unstable marriage, Unstable close relationship, Lovelessness, Modernisation, Low-density neighbourhood. Of these, old age and low-density neighbourhood are the greatest culprits.
1. Mental abuse
This can easily happen in schools where one student could be taunted by others or bullied may be because some other students consider him weak or ugly or of questionable parentage. The affected student will naturally withdraw into a shell of loneliness though a few do fight back, becoming very violent. Some are unable to take the abuse and end up committing suicide.
2. Inability to fit in
Some persons do have low esteem of themselves, they believe they are worthless and as such feel unworthy of relating with others. They believe they cannot fit in, do not belong to any group as no one will listen to them. This can lead to loneliness.
The relationship between depression and loneliness is complex. Loneliness can be caused by depression and vice versa. The depression could be after delivery of a baby, loss of a loved one, divorce, a heart break; all these could lead to exit from a social circle apart from missing the loved one.
Sometimes the reason for depression cannot be identified.
4. Age (old age)
Old age could be very lonely, all the children have grown up and moved out. Some children cut off entirely while a few call by phone on special occasions like birthday, Christmas day etc. The loneliness increases with the deaths of friends and contemporaries.
5. Unstable marriage/close relationship
In an unstable marriage or relationship, a spouse who feels unloved or neglected is likely to feel lonely. This appears more common with women especially in societies where it is uncommon for women to go out alone
Movement to a new community where there are no friends or family members can be a cause of depression. The person feels isolated with no one to spend free time with or confide in. The person longs for the former community.
7. Low-density neighbourhood
Low density neighbourhood can cause loneliness, everyone keeps to himself in the name of modernization. You are unlikely to know your next door neighbour so you cannot stroll across for a drink or watch a game together. Everyone is to himself.
Also Read Health effects of Loneliness