Abnormal behavior is any type of behavior which does not come in the boundaries of the regular and sane. The legally acceptable definition of abnormal behavior is when the individual is unable to spot the difference between right or wrong. However psychologists make use of multiple criteria that identify whether an individual is abnormal.
The first criteria that is use to define abnormal behavior is determining whether the behavior deviates from the statistical norm. This requires taking statistical measurements of the population in terms of intelligence. Most of the population tends to fall in the average zone, but those people who are having extremely low intelligence or very high intellect, they are said to be depicting abnormal behavior and behavioral tendencies.
The second criterion deals with deviation from the social norms. For this the attitude and the behavior of the individual is observed and determined pertaining to the social circle around him/ her. This enables us to identify whether individual depicts normally accepted social behavior, or is in constant violation of them. The violation of social norms can lead to and indicate abnormal behavior.
The third criterion pertains to the personal distress of the individual. In this it is considered whether the abnormality in the behavior is occurring due to the subject undergoing distress. Abnormal behavior in people can also be attributed to high levels of tension and anxiety. The abnormality of neurosis is specifically dependent on personal distress. Lastly another criterion can be used to define abnormality. This relates to how the behavior of the individual affects the social life of the individual as well as their health and mental state. This includes cases where the individual might be indulging in drugs, alcohol, as well as paranoia.