HISTORY

In the United States, the initial interest in developing a classification of disorders started in the 1800s in order to collect statistical information. In 1840, this consisted of recording the category of idiocy or insanity. By 1880, the census distinguished between mania, melancholia, monomania, paresis, dementia, dipsomania, and epilepsy. In 1917, the American Medico-Psychological Association (a forerunner of the American Psychiatric Association [APA]) adopted a plan to collect uniform information across mental hospitals. The APA subsequently collaborated with the New York Academy of Medicine to develop a nationally acceptable nomenclature that was incorporated into the first edition of the American Medical Association’s Standard Classified Nomenclature of Disease. Later, a broader nomenclature was developed by the U.S. Army in order to better incorporate the outpatient presentations of veterans of World War II. At around the same time, the World Health Organization published the sixth edition of its International Classification of Diseases (ICD-6), which for the first time included a mental disorders section that included psychoses (10 categories); psychoneuroses (9 categories); and disorders of character, behavior, and intelligence (7 categories).

The APA published a variation of the ICD-6 mental disorders categories in 1952, as the first edition of the Diagnostic Statistical Manual of Mental Disorders (DSM), and it was first revised in 1967.⁷ Both of these editions were influenced predominantly by a psychoanalytic approach, and the term reaction was used for many of the disorders, more so in the first edition. For example, in 1967, what is now defined as attention-deficit/hyperactivity disorder (ADHD) was still labeled hyperkinetic reaction of childhood. The classificatory structure was organized with two poles: psychosis on the severe end, characterized by a disconnection with reality and typically manifested by hallucinations, delusions, and illogical thinking, and neurosis at the mild end, characterized by distortions of reality and typically manifested by anxiety and depression.

In 1980, when the DSM was revised to the third edition,⁸ the psychodynamic view was discarded, and a biomedical model became the principal approach. The system included explicit diagnostic criteria and a multiaxial system. The revised system tried to make a clear distinction between normal and abnormal. The revision of the third edition, DSM-III-R,⁹ was published in 1987 and was based on additional research and consensus. It was subsequently revised again in 1994 as the fourth edition (DSM-IV),¹⁰ in part to develop compatibility between the DSM system and the tenth edition of the International Classification of Diseases (ICD-10).¹¹ Additional revisions in the text were published in 2000 without any substantial changes in the disorder characteristics (DSM-IV-TR).¹²

ORGANIZATIONAL PLAN

The DSM-IV system has become the most well established and widely used of diagnostic classification systems in clinical practice with children with behavioral disorders. The DSM-IV system is divided into five axes to provide for the assessment of multiple domains of information. These axes are described as follows.

ADDITIONAL INFORMATION

The DSM-IV manual also includes the following areas of additional information that may be important to diagnostic and treatment planning: (1) variations in the presentation of the disorder that are attributable to cultural setting, developmental stage (e.g., infancy, childhood, adolescence, adulthood, late life), or gender (e.g., sex ratio); (2) prevalence, which includes data on point and lifetime prevalence, incidence, and lifetime risk as available for different settings; (3) course, which consists of typical lifetime patterns of presentation and evolution of the disorder: age at onset and mode of onset (e.g., abrupt or insidious) of the disorder; episodic versus continuous course; single versus recurrent episodes; and duration and progression (e.g., the general trend of the disorder over time); (4) familial pattern (e.g., data on the frequency of the disorder among first-degree biological relatives and family members in comparison with the general population); and (5) differential diagnosis.

CLINICAL USE AND LIMITATIONS

The DSM system has become the standard for diagnosing mental disorders. It provides criteria for establishing diagnoses of mental disorders in the United States and other countries. The criteria are widely accepted for both research and clinical purposes, and both structured interviews and rating scales have been developed on the basis of this system. Third-party payers have used the system as their basis for reimbursement, and federal and state agencies use the diagnostic categories for providing services and funding research.

Despite its broad utility, however, the DSM is by no means a perfect system from a scientific and clinical standpoint in the field of developmental-behavioral pediatrics. Limitations of this system include the fact that it is not developmentally based and provides only a dichotomy of disorders, being present or absent, rather than a continuum. Moreover, the same diagnostic criteria are required for all patients regardless of age. In addition, the DSM system addresses developmental issues inconsistently. For example, in conditions such as mental retardation or learning disabilities, the testing process to establish the diagnosis provides for the variations anticipated for age. On the other hand, conditions such as ADHD or major depressive disorder require the same number of behavioral manifestations regardless of age. Developmental changes can be used to define the appropriate manifestation or frequency of particular behaviors, but developmental criteria remain loosely defined and therefore very subjective.

A critical assumption in the DSM system is that an individual’s symptoms either meet the criteria for a particular disorder or fall within a normal range. However, many of the characteristics of the disorders may be present in varying degrees along a spectrum. This situation can be present in children who manifest behaviors severe enough to cause problems for the child but not severe enough to be characterized as a disorder. Children in this situation have been referred to as having a “subthreshhold” condition. Children with subthreshhold conditions have tended to be much more of a focus in primary care settings than in the mental health service sector.

The occurrence of behavioral symptoms along a spectrum leads to much subjectivity in defining the boundaries of many disorders. The difficulty has been most prominent for ADHD, resulting in concerns about how many children receive a diagnosis of this condition¹⁴ and wide variations in the prevalence rates of how many children are being treated for the condition.¹⁵

HISTORY

A unified classification of diseases started in 1853 at the First International Statistical Congress. The Bertillon Classification of Causes of Death was a synthesis of English, German, and Swiss classifications that was general accepted internationally at the end of the 19th century and was accepted by the American, Canadian, and Mexican organizations in 1898. In 1929, a Mixed Commission made up of representatives of the International Statistical Institute and the Health Organization of the League of Nations developed the Fourth Revision of the International List of Causes of Death; this was revised as the fifth edition in 1938. A recognition that morbidity needed to be included started in the earlier 1900s, so that the fourth revision included further subdivisions to reflect morbid conditions that were not causes of death. The sixth edition, titled International Classification of Diseases, was entrusted to the Interim Commission of the World Health Organization in 1948.

In the early 1960s, the Mental Health Program of the World Health Organization worked to improve the diagnosis and classification of mental disorders. These activities resulted in major revisions in the mental disorders, classified in the eighth edition. In both the eighth and ninth revisions, like DSM-II, the system contained the divisions between neurotic and psychotic disorders. However, the 10th edition (ICD-10), published in 1992,¹¹ took a more atheoretical approach, similar to that of DSM-IV. The number of categories expanded from 30 in ICD-9 to 100 in ICD-10.

ORGANIZATIONAL PLAN

The mental disorders in ICD-10 are divided into ten categories: organic, including symptomatic, mental disorders (F00-09); mental and behavioral disorders caused by psychoactive substance use (F10-19); schizophrenia, schizotypal, and delusional disorders (F20-29); mood (affective) disorders (F30-39); neurotic, stress-related, and somatoform disorders (F40-49); behavioral syndromes associated with physiological disturbances and physical factors (F50-59); disorders of adult personality and behavior (F60-69); mental retardation (F70-79); disorders of psychological development (F80-89); and behavioral and emotional disorders with the onset usually occurring in childhood and adolescence (F90-98). The behavioral and emotional disorders with onset usually occurring in childhood and adolescence and the disorders of psychological development are presented in Table 6-2.

TABLE 6-2 ICD-10: Behavioral and Emotional Disorders with Onset Usually Occurring in Childhood and Adolescence and Disorders of Psychological Development