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1.7: Diagnosing and Classifying Mental Disorders

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    Learning Objectives
    • Describe the basic features of the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) and how it is used to classify disorders
    • Outline the major disorder categories of the DSM-5

    A first step in the study of mental disorders is carefully and systematically discerning significant signs and symptoms. How do mental health professionals ascertain whether or not a person’s inner states and behaviors truly represent a psychological disorder? Arriving at a proper diagnosis—that is, appropriately identifying and labeling a set of defined symptoms—is absolutely crucial. This process enables professionals to use a common language with others in the field and aids in communication about the disorder with the patient, colleagues, and the public. A proper diagnosis is an essential element to guide proper and successful treatment. For these reasons, classification systems that organize psychological disorders systematically are necessary.

    Diagnostic and Statistical Manual of Mental Disorders (DSM-5)

    Although a number of classification systems have been developed over time, the one that is used by most mental health professionals in the United States is the Diagnostic and Statistical Manual of Mental Disorders (DSM-5), published by the American Psychiatric Association in 2013. Additions and revisions were made in March 2022, so the most current edition is called the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, Text Revision (DSM-5-TR). (Note that the American Psychiatric Association differs from the American Psychological Association; both are abbreviated APA.) This textbook includes the updates from the DSM-5-TR, though we typically continue to reference the diagnostic manual simply as the DSM-5.

    The first edition of the DSM, published in 1952, classified psychological disorders according to a format developed by the U.S. Army during World War II (Clegg, 2012). In the years since, the DSM has undergone numerous revisions and editions. The DSM-5 includes many categories of disorders (e.g., anxiety disorders, depressive disorders, and dissociative disorders). Each disorder is described in detail, including an overview of the disorder (diagnostic features), specific symptoms required for diagnosis (diagnostic criteria), prevalence information (what percent of the population is thought to be afflicted with the disorder), and risk factors associated with the disorder. Figure \(\PageIndex{1}\) shows lifetime prevalence rates—the percentage of people in a population who develop a disorder in their lifetime—of various psychological disorders among U.S. adults. These data were based on a national sample of 9,282 U.S. residents (National Comorbidity Survey, 2007).

    A bar graph has an x-axis labeled “DSM disorder” and a y-axis labeled “Lifetime prevalence rates.” For each disorder, a prevalence rate is given for total population, females, and males. Appropriate alternative text can be found in the data table displayed below this image. The approximate data shown is: “major depressive disorder” 17% total, 20% females, 13% males; “alcohol abuse” 13% total, 7% females, 20% males; “specific phobia” 13% total, 16% females, 8% males; “social anxiety disorder” 12% total, 13% females, 11% males; “drug abuse” 8% total, 5% females, 12% males; “posttraumatic stress disorder” 7% total, 10% females, 3% males; “generalized anxiety disorder” 6% total, 7% females, 4% males; “panic disorder” 5% total, 6% females, 3% males; “obsessive-compulsive disorder” 3% total, 3% females, 2% males; “dysthymia” 3% total, 3% females, 2% males.
    Figure \(\PageIndex{1}\): The graph shows the breakdown of psychological disorders, comparing the percentage prevalence among adult males and adult females in the United States. Because the data is from 2007, the categories shown here are from the DSM-4, which has been supplanted by the DSM-5. Most categories remain the same; however, alcohol abuse now falls under a broader alcohol use disorder category.
    Table \(\PageIndex{1}\). DSM Disorder Lifetime Prevalence Rates
    DSM Disorder Total Females Males
    Major Depressive Disorder 17% 20% 13%
    Alcohol Abuse 13% 7% 20%
    Specific Phobia 13% 16% 8%
    Social Anxiety Disorder 12% 13% 11%
    Drug Abuse 8% 5% 12%
    Post-Traumatic Stress Disorder 7% 10% 3%
    Generalized Anxiety Disorder 6% 7% 4%
    Panic Disorder 5% 6% 3%
    Obsessive-Compulsive Disorder 3% 3% 2%
    Dysthymia 3% 3% 2%

    More recent data shows that the most prevalent disorders in any given time (not over a lifetime) are anxiety disorders, as shown in the following chart.[1]

    Prevalence by mental and substance use disorder (2017). Data shows anxiety disorders as most prevalent at 6.64%, depression 4.84%, drug use 3.45%, alcohol use at 2.04%, bipolar 0.65%, eating disorders 0.51%, and schizophrenia 0.33%.
    Figure \(\PageIndex{2}\): The prevalence of mental and substance use disorders in the United States.

    The DSM-5 also provides information about comorbidity; the co-occurrence of two disorders. For example, the DSM-5 mentions that 41% of people with obsessive-compulsive disorder (OCD) also meet the diagnostic criteria for major depressive disorder (Figure \(\PageIndex{2}\)). Drug use is highly comorbid with other mental illnesses; six out of 10 people who have a substance use disorder also suffer from another form of mental illness (National Institute on Drug Abuse [NIDA], 2007).

    A Venn-diagram shows two overlapping circles. One circle is titled “Obsessive-Compulsive Disorder” and the other is titled “Major Depressive Disorder.” The area in which these two circles overlap includes forty-one percent of each circle. This area is titled “Comorbidity 41%.”
    Figure \(\PageIndex{3}\): Obsessive-compulsive disorder and major depressive disorder frequently occur in the same person.

    Comorbidity

    Co-occurrence and comorbidity of psychological disorders are quite common, and some of the most pervasive comorbidities involve substance use disorders that co-occur with psychological disorders. Indeed, some estimates suggest that around a quarter of people who suffer from the most severe cases of mental illness exhibit substance use disorder as well. Conversely, around 10 % of individuals seeking treatment for substance use disorder have serious mental illnesses. Observations such as these have important implications for treatment options that are available. When people with a mental illness are also habitual drug users, their symptoms can be exacerbated and resistant to treatment. Furthermore, it is not always clear whether the symptoms are due to drug use, the mental illness, or a combination of the two. Therefore, it is recommended that behavior is observed in situations in which the individual has ceased using drugs and is no longer experiencing withdrawal from the drug in order to make the most accurate diagnosis (NIDA, 2018).

    Obviously, substance use disorders are not the only possible comorbidities. In fact, some of the most common psychological disorders tend to co-occur. For instance, more than half of individuals who have a primary diagnosis of depressive disorder are estimated to exhibit some sort of anxiety disorder. The reverse is also true for those diagnosed with a primary diagnosis of an anxiety disorder. Further, anxiety disorders and major depression have a high rate of comorbidity with several other psychological disorders (Al-Asadi, Klein, & Meyer, 2015).

    Watch It

    This video provides an overview of some of the history related to the development and evolution of the DSM.

    You can view the transcript for “We Were Super Wrong About Mental Illness: The DSM’s Origin Story” here (opens in new window).

    Beginning with the DSM-3 in 1980, mental disorders have been described in much greater detail, and the number of diagnosable conditions has grown steadily, as has the size of the manual itself. DSM-1 included 106 diagnoses and was 130 total pages, whereas DSM-3 included more than twice as many diagnoses (265) and was nearly seven times its size (886 total pages) (Mayes & Horowitz, 2005). Although DSM-5 is longer than DSM-4, the volume includes only 237 disorders, a decrease from the 297 disorders that were listed in DSM-4. The latest edition, DSM-5, includes revisions in the organization and naming of categories and in the diagnostic criteria for various disorders (Regier, Kuhl, & Kupfer, 2012), while emphasizing careful consideration of the importance of gender and cultural difference in the expression of various symptoms (Fisher, 2010).

    Some believe that establishing new diagnoses might over pathologize the human condition by turning common human problems into mental illnesses (The Associated Press, 2013). Indeed, the finding that nearly half of all Americans will meet the criteria for a DSM disorder at some point in their life (Kessler et al., 2005) likely fuels much of this skepticism. The DSM-5 is also criticized on the grounds that its diagnostic criteria have been loosened, thereby threatening to “turn our current diagnostic inflation into diagnostic hyperinflation” (Frances, 2012, para. 22). For example, DSM-4 specified that the symptoms of major depressive disorder must not be attributable to normal bereavement (loss of a loved one). The DSM-5, however, has removed this bereavement exclusion, essentially meaning that grief and sadness after a loved one’s death can constitute major depressive disorder.

    Try It

    Categories in the DSM

    The DSM-5 is divided into 22 chapters that include sets of related disorders. This organization is evident in every chapter so that related disorders appear closer to each other, and psychological and biological diseases often relate to each other. However, if an illness that is primarily medical is not specified in DSM-5, clinicians may use the current ICD diagnoses to specify the condition.

    Link to Learning

    View the DSM-5 Table of Contents here. Note that the overall outline is the same in the DSM-5-TR, though the contents and some of the language have changed slightly. For example, “dysthymia” is no longer used to describe “persistent depressive disorder,” the terminology for “intellectual disability” has been replaced with “intellectual development disorder” and “conversion disorder” is better known as “functional neurological symptom disorder.” A new disorder, prolonged grief disorder, was added to the section on trauma- and stressor-related disorders.

    The current organization of the DSM-5 begins with neurodevelopmental disorders and then proceeds through internalizing problems (depression, anxiety, social anxiety, somatic complaints, post-traumatic symptoms, and obsession-compulsion) to externalizing problems (disruptive, impulse-control, conduct disorders and substance use, etc.). [2]

    We have organized this course according to the DSM-5 and devote time in each of the modules to discuss the main features of mental disorders from each of the DSM-5 categories. Throughout these modules, you will learn the basic diagnostic criteria, the etiology (causes), epidemiology (prevalence), and treatment options for each category of disorders. In this way, you can gain a basic understanding of each category of mental disorders, including all of the following:

    1. neurodevelopmental disorders
    2. schizophrenia spectrum and other psychotic disorders
    3. bipolar and related disorders
    4. depressive disorders
    5. anxiety disorders
    6. obsessive-compulsive and related disorders
    7. trauma- and stressor-related disorders
    8. dissociative disorders
    9. somatic symptom and related disorders
    10. feeding and eating disorders
    11. elimination disorders
    12. sleep-wake disorders
    13. sexual dysfunctions
    14. gender dysphoria
    15. disruptive, impulse-control, and conduct disorders
    16. substance-related and addictive disorders
    17. neurocognitive disorders
    18. personality disorders
    19. paraphilic disorders
    20. Other mental disorders[3]
    Glossary

    comorbidity: co-occurrence of two disorders in the same individual

    diagnosis: determination of which disorder a set of symptoms represents

    Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5): authoritative index of mental disorders and the criteria for their diagnosis; published by the American Psychiatric Association (APA)

    externalizing problems: problems related with disruptive behavior that cause conflicts in relationships with others

    internalizing problems: problems that involve emotional alterations of anxiety disorders and depression

    1. Hannah Ritchie and Max Roser (2018) - "Mental Health". Published online at OurWorldInData.org. Retrieved from: 'https://ourworldindata.org/mental-health' [Online Resource] ↵
    2. Salavera, Carlos, Usán, Pablo, & Teruel, Pilar. (2019). The relationship of internalizing problems with emotional intelligence and social skills in secondary education students: gender differences. Psicologia: Reflexão e Crítica, 32, 4. Epub February 18, 2019. https://dx.doi.org/10.1186/s41155-018-0115-y↵
    3. Regier, D. A., Kuhl, E. A., & Kupfer, D. J. (2013). The DSM-5: Classification and criteria changes. World psychiatry: official journal of the World Psychiatric Association (WPA), 12(2), 92–98. https://doi.org/10.1002/wps.20050↵
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