- Define “psychological disorder” and summarize the general causes of disorder.
- Explain why it is so difficult to define disorder, and how the Diagnostic and Statistical Manual of Mental Disorders (DSM) is used to make diagnoses.
- Describe the stigma of psychological disorders and their impact on those who suffer from them.
The focus of the next two chapters is to many people the heart of psychology. This emphasis on abnormal psychology—the application of psychological science to understanding and treating mental disorders—is appropriate, as more psychologists are involved in the diagnosis and treatment of psychological disorder than in any other endeavor, and these are probably the most important tasks psychologists face. About 1 in every 4 Americans (or over 78 million people) are affected by a psychological disorder during any one year (Kessler, Chiu, Demler, & Walters, 2005), and at least a half billion people are affected worldwide. The impact of mental illness is particularly strong on people who are poorer, of lower socioeconomic class, and from disadvantaged ethnic groups.
People with psychological disorders are also stigmatized by the people around them, resulting in shame and embarrassment, as well as prejudice and discrimination against them. Thus the understanding and treatment of psychological disorder has broad implications for the everyday life of many people. Table 12.1 “One-Year Prevalence Rates for Psychological Disorders in the United States, 2001–2003” shows the prevalence (i.e., the frequency of occurrence of a given condition in a population at a given time) of some of the major psychological disorders in the United States.