Defining Abnormal

Although defining abnormal does not always prove easy, psychologists use a set of criteria to help them determine and define behavior that is outside of the norm. During assessments, mental health professionals question whether behaviors are typical of people in that culture, impair daily functioning, or have potential to cause harm to self or others. Further considerations include severity and duration of behaviors.

Classification systems, like the most commonly used DSM, exist to categorize abnormal behaviors. Specifically, the American Psychological Association (APA) developed the DSM. This resource has categorized abnormal behaviors, and also includes its cluster symptoms. The DSM is a work in progress that goes through continual revisions as knowledge about abnormal behavior increases.