Alienation & Loss of sense of belonging

What causes an individual to feel a sense of not belonging in the family unit in which they lived and enjoyed before?

Both young people and adults sometimes feel alienated although no one person might have specifically caused it. It is usually a combination of factors such as their early childhood experiences, past or present relationships and unresolved issues in their lives. They also feel they have no one they trust enough to talk to about their problems. They think everyone perceives them the way they falsely think about themselves.
Problems arise when someone feels left out or rejected - of being separate from and not fitting in with the rest of the group. Such persons tend to adopt negative behaviors and are often given nicknames and labels. Their behaviors compound their problems and they tend to adopt and identify with the label or name.
Alienation is an emotional isolation of self from where one should be or used to be - a feeling of loss of not being a part of the family unit, group or community.

Alienation leads to certain destructive behaviors such as:

Alone-ness/Loner – “Leave me alone, I don’t need anybody”
School drop outr
Negative behaviors (bullying, fighting, cursing & vulgarity)
Self-loathing & Poor Body Image (Cutting, Anorexia/Bulimia)
Drug Use
Anger
Hater
Gang violencer
Criminality

These behaviors tend to escalate over time. In order to help such individuals modify their behaviors, serious efforts and investment of resources of several professional experts have to sought to help them regain what was lost and be made to feel a sense of belonging again.