Diagnosis of Psychological Disorders

The diagnosis of a psychological disorder requires evaluation by a trained mental‐health professional and usually an interview, administration of a variety of personality tests (and in some cases, neuropsy‐chological tests), and gathering of background (including medical) information about the individual. The mental‐health professional arrives at a diagnosis by comparing this information to that in the Diagnostic and Statistical Manual of Mental Disorders , the DSM‐IV (IV for fourth edition, 1994), which uses a system devised by the American Psychiatric Association to classify psychological disorders. The classification system, which lists 16 categories of maladjustment and more than 200 subcategories, is designed to improve the reliability of diagnoses by using observable behaviors to categorize disorders and to ensure that diagnoses are consistent with current information. Diagnosis using this resource requires the use of five dimensions, or axes. Judgments must be made on each of the five axes, and a diagnostician must consider a broad range of information in making the diagnosis.

The classification of abnormal behavior is made on the basis of Axis I (Clinical Syndromes) and Axis II (Personality Disorders). Patients may receive a diagnosis on both axes; the milder, long‐standing personality disorders of Axis II may coexist with Axis I syndromes. The remaining three axes— Axis III (General Medical Conditions), Axis IV (Psychosocial and Environmental Problems), and Axis V (Global Assessment of Functioning)—are used to provide supplementary information. Use of the combined axes, which include the individual's history and highest level of competent functioning in the past year, ensures that a person not only will be assigned to a mental‐disturbance category but also will be characterized by a number of relevant clinical factors.

Use of a classification system permits mental‐health professionals to communicate accurately, helps in the determination of effective treatments, facilitates the use of research data on a particular category, and assists in making predictions. Classification systems, however, are based upon judgments of professionals and can change over time as new information is collected. Controversy still exists over the DSM‐IV system; it is revised as new research information becomes available. Diagnostic categories have been deleted or changed. For example, “homosexuality” has been excluded as a mental‐disturbance category, and arguments about use of the category “premenstrual syndrome” have resulted in the condition's being moved to the appendix, where it is called “premenstrual dysphoric disorder” and listed as needing more study. The category termed “ neuroses” has not been included since the 1980 edition. The term “ psychosis” is still used for conditions such as schizophrenia, which are characterized by bizarre behavior and beliefs, delusions, and loss of contact with reality.