Defining abnormal behavior

What is Abnormal?
Before we can write about specific behavioral disorders, we must define 'abnormal'. And what is normal behavior?
The following criteria are used to determine wheter a persons behavior is abnormal or not:

Deviation from statistical norms;the word abnormal means 'away from the norm'. Many population facts are measured such as height, weight and intelligence. Most of the people fall within the middle range of intelligence, but a few are abnormally stupid. But according to this definition, a person who is extremely intelligent would be classified as abnormal. Thus in defining abnormal behavior we must consider more.
Deviation from social norms; every vulture has certain standards for acceptable behavior; behavior that deviates from that standard is considered to be abnormal behavior. But those standards can change with time and vary from one society to another.
Maladaptiveness of behavior; this third criterium is how the behavior affects the well-being of the individual and/or social group. Examples are a man who attempts suicide, an alcoholic who drinks so heavily that he or she cannot keep a job or a paranoid individual who tries to assasinate national leaders.
Personal distress; the fourth criterium considers abnormality in terms of the individual's subjective feelings, personal distress, rather than his behavior. Most people diagnosed as 'mentally ill' feel miserable, anxious, depressed and may suffer from insomnia.
In the type of abnormality called neurosis, personal distress may be the only symptom, because the individual's behavior seems normal.