Published by the American Psychiatric Association (APA), the DSM is the standard classification of mental disorders used by mental health professionals in the United States. There have been six editions of this collection of psychiatric nomenclature, each edition designated by a number. Historically the DSM has its genesis in the US War Department’s Technical Bulletin 203 of 1946, the Standard Classified Nomenclature of Disease of 1942, and the Veterans Administration Nomenclature. The Medical 203 contained 47 mental illness diagnoses and it most heavily influenced what was to become DSM-I.

The fourth edition of the DSM (DSM-IV) was published in 1994. It contained 365 diagnoses and represented a leap forward in psychiatry in that it has eschewed the distinction between the mental and physical, considering it passé. It is unclear at this writing when a completely new DSM (DSM-V) will be ready for publication. However, because of new research information developed since the 1994 publication of DSM-IV, the APA revised its text in 2000. These text revisions (DSM-IV-TR) are minor and limited to criteria for “personality change due to a medical condition,” several of the paraphilias (sexual disorders), and Tourette’s disorder. In the latter two, it was no longer necessary that the person with the disorder suffer distress or impaired functioning.

The DSM is intended to be applicable in a wide array of contexts and used by clinicians and researchers of many different orientations including biological, psychodynamic, cognitive, behavioral, interpersonal. The manual is designed to be used across settings that include inpatient, outpatient, partial hospital, consultation-liaison, clinic, private practice, primary care, and with community populations. It is used by psychiatrists, psychologists, social workers, nurses, occupational and rehabilitation therapists, counselors, and other health and mental health professionals. It is a necessary tool for collecting and communicating among professionals.

The DSM consists of three major components: the diagnostic classification, the diagnostic criteria sets, and the descriptive text. The diagnostic classification is the list of the mental disorders that are officially part of the DSM system. Making a diagnosis consists of selecting those disorders from the classification that best reflect the signs and symptoms that are afflicting the individual being evaluated. Associated with each diagnostic label is a code, which is typically used by institutions and agencies for data collection and billing. These diagnostic codes are derived from the coding system used by all healthcare professionals in the US, known as the International Classification of Diseases (ICD-10) which will be discussed in a subsequent section of this chapter.

For each disorder included in the DSM, a set of diagnostic criteria indicates what symptoms must be present (and for how long) in order to qualify for a diagnosis, as well as the symptoms or conditions that must not be present. These are deemed “inclusion” and “exclusion” criteria.

The third component of the DSM is the descriptive text that accompanies each disorder. The text of the DSM systematically describes each disorder under the following headings: diagnostic features, subtypes and/or specifiers, recording procedures, associated features and disorders, specific culture, age and gender features, prevalence, course, familial pattern, and differential diagnosis.

The DSM uses a five-axis system to give a more comprehensive picture of the client’s functioning. The five axes are as follows:

• Axis I – Clinical disorders consisting of all relevant major psychiatric disorders (e.g., schizophrenia, bipolar disorders, major depression).
  
• Axis II – Personality disorders and mental retardation (personality disorders as defined in the DSM-IV-TR are “deeply ingrained maladaptive, lifelong behavior patterns”).
  
• Axis III – General medical conditions that are identified on the basis of a comprehensive history and physical examination, evaluation of symptoms, mental state examination, and supplementary assessment instruments. These include any medical condition (e.g., diabetes, hypertension, cystic fibrosis).
  
• Axis IV – Psychosocial and environmental problems (these can include stressors such a recent death of a loved one, being a victim of a crime, going through a divorce, losing one’s job, among others).
  
• Axis V – Global assessment of functioning (GAF), written as numbers (0–100) meaning “current functioning”/“highest level of functioning in past year” with 100 being the highest optimization of functioning and 0 being the lowest.

Many patients have more than one diagnosis on the first three axes. This is known as comorbidity