Abnormal behavior

Abnormality (or dysfunctional behavior), in the vivid sense of something deviating from the normal or differing from the typical (such as an ), is a subjectively defined behavioral characteristic, assigned to those with rare or dysfunctional conditions. Behavior is considered abnormal when it is atypical, out of the ordinary, causes some kind of impairment, or consists of undesirable behavior. Who is normal or abnormal is a contentious issue in abnormal psychology.

There are five main criteria of abnormality. They are 1. statistical criterion 2. social criterion 3. personal discomfort 4. maladaptive behaviour 5. deviation from ideal

According to "Essentials of Abnormal Psychology" by Durand and Barlow, abnormal behaviors are "actions that are unexpected and often evaluated negatively because they differ from typical or usual behavior."

A common approach to defining abnormality is a Multi-Criteria approach, where all definitions of abnormality are used to determine whether an individuals behavior is abnormal. For example, if an individual is engaging in a particular behavior that is preventing them from 'functioning', breaks a social norm and is statistically infrequent, then psychologists would be prepared to define this individual's behavior as abnormal. A good example of an abnormal behavior assessed by a multi-criteria approach is depression: it is commonly seen as a deviation from ideal mental stability, it often stops the individual from 'functioning' a normal life, and, though it is a relatively common mental disorder, it is still statistically infrequent. Most people do not experience significant major depressive disorder in their lifetime ³.

¹NIMH factsheet on frequency of mental disorders.
²Article on complicated grief.
³Article on results of the National Comorbidity Study

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