This is the 2007 version. Click here for the 2017 chapter 12 table of contents.

Summary: Defining Abnormal Behavior

Abnormal behavior can be defined in several different ways. More than ever, abnormal behavior syndromes such as schizophrenia, depression, and alcoholism are being related to genetics and brain diseases. However, as a practical matter, society intervenes when an abnormal behavior becomes a "harmful dysfunction"-that is, when a person seems to be doing real harm to self or others.

A social movement called deinstitutionalization spread throughout the United States and Canada in the 1960s and 1970s. Within a few decades, people were no longer being forced to stay in mental institutions against their will, unless it could be shown that they presented a "clear and present danger" to themselves or somebody else.

One problem with deinstitutionalization—the policy of releasing many people from mental hospitals—was that few community support services existed to care for people who were not able to care for themselves. Many of them ended up living on the streets. Homeless people became increasingly common in large North American cities during the 1970s and 1980s. Up to 60% of so-called "homeless" people had an identifiable mental disorder. In 1990 there were 3,600 "seriously mental ill" inmates in the Los Angeles County jail alone, making it the largest "de facto mental hospital" in the United States.

Mental health clinicians use a reference manual called DSM, the Diagnostic and Statistical Manual of the American Psychiatric Association, to classify mental disorders. This volume, currently in its fourth edition, is revised every few years. It provides a diagnostic shorthand for clinicians of all different types and encourages a thorough work-up of clients using several different dimensions or axes.

Write to Dr. Dewey at

Don't see what you need? Psych Web has over 1,000 pages, so it may be elsewhere on the site. Do a site-specific Google search using the box below.

Custom Search

Copyright © 2007-2011 Russ Dewey