Diagnosis can be defined as the identification and labeling of a disease based on its signs and symptoms. Mental health clinicians (psychiatrists, psychologists, and psychiatric nurse practitioners) diagnose mental disorders using the criteria listed in the Diagnostic and Statistical Manual of Mental Disorders, also known as the DSM, published by the American Psychiatric Association.
According to the DSM, fourth edition, text revised (the DSM-IV-TR), the term mental disorder is unfortunate because it implies that a mental disorder is separate from a physical illness, when actually, according to the American Psychiatric Association (APA), researchers and scientists now know that that distinction is not a clear one to make. The APA argues that "there is much 'physical' in 'mental disorders' and much 'mental' in 'physical disorders,'" and continues to use the term "mental disorders" because a better term has not yet been found. The APA defines a mental disorder as "a clinically significant behavioral or psychological syndrome or pattern that occurs in an individual and that is associated with present distress or disability or with a significantly increased risk of suffering death, pain, disability, or an important loss of freedom." Many people fear that when a mental disorder is classified, people are actually classified, and the DSM-IV-TR strives to contradict this notion. The American Psychiatric Association believes their manual to be strictly a manual classifying mental disorders themselves, and does not advocate the use of the diagnoses to discriminate.
The manual lists various criteria for each mental disorder included in the book. When an individual seeks the help of a mental health clinician, the clinician interviews the client (along with family members when appropriate), gathers a medical history, and may administer psychological evaluations (various checklists or tests that the patient may complete) in order to establish a diagnosis. Once the clinician has gathered the necessary information, a diagnosis based on the symptoms may be assigned from the DSM.
One of the main purposes of diagnosis is to guide treatment planning. If doctors know that a particular disorder has shown to be treated effectively with a drug or with a specific therapy, then the best practice can be applied to a new case of that disorder. The diagnosis also helps to establish a prognosis for the patient and his or her family, and it helps to enable communication among the professionals (including insurers) involved in a patient's care. Additionally, a formal diagnosis as recognized by the DSM may be necessary in order for insurers to pay for medical services. The act of labeling a mental disorder may have unintended effects for the person with the disorder, however. Although the DSM states that its diagnoses do not label people, in reality, many people who have received diagnoses of mental disorders may feel affected by the label their disorder has been given. People diagnosed with mental disorders may feel stigmatized, and that others' perceptions of them—as well as their self-perceptions— have changed as a result of their diagnosis.
Allen, John J. B. "DSM-IV." In Encyclopedia of Mental Health, edited by Howard S. Friedman. San Diego, CA: Academic Press, 1998.
American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders. Fourth edition, text revised. Washington DC: American Psychiatric Association, 2000.