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12.1: Psychological Disorder: What Makes a Behavior “Abnormal”?

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    Learning Objectives

    1. Define “psychological disorder” and summarize the general causes of disorder.
    2. 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.
    3. 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 psychologythe 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.

    Table 12.1 One-Year Prevalence Rates for Psychological Disorders in the United States, 2001–2003

    Disease Percentage affected Number affected
    Any mental disorder 26.2 81,744,000
    Any anxiety disorder 18.1 56,472,000
    Specific phobia 8.7 27,144,000
    Social phobia 6.8 21,216,000
    Agoraphobia 0.8 2,496,000
    Generalized anxiety disorder 3.1 9,672,000
    Panic disorder 2.7 8,424,000
    Obsessive-compulsive disorder 1.0 3,120,000
    Posttraumatic stress disorder 3.5 10,920,000
    Any mood disorder 9.5 29,640,000
    Major depressive disorder 6.7 20,904,000
    Bipolar disorder 2.6 8,112,000
    Schizophrenia 1.0 3,120,000
    Personality disorders
    Antisocial personality disorder 1.5 4,680,000
    Borderline personality disorder 1.5 4,680,000
    Anorexia nervosa 0.1 312,000
    Any substance abuse disorder 3.8 11,856,000
    Alcohol use disorder 4.4 13,728,000
    Drug use disorder 1.8 5,616,000
    All cancers* 5.4 16,848,000
    Diabetes* 10.7 33,348,000
    * These nonpsychological conditions are included for comparison.

    Sources: Kessler, R. C., Chiu, W. T., Demler, O., & Walters, E. E. (2005). Prevalence, severity, and comorbidity of 12-month DSM-IV disorders in the National Comorbidity Survey Replication. Archives of General Psychiatry, 62(6), 617–627; Narrow, W. E., Rae, D. S., Robins, L. N., & Regier, D. A. (2002). Revised prevalence based estimates of mental disorders in the United States: Using a clinical significance criterion to reconcile 2 surveys’ estimates. Archives of General Psychiatry, 59(2), 115–123.