Diagnosing Mental Illness

Although new technology has improved our ability to study the living brain, there is no definitive laboratory test, scan, or biopsy for mental illness. This makes the diagnosis of mental disorders more difficult than the diagnosis of most other medical disorders.

Until scientists develop physiological tests, mental health professionals will have to diagnose mental illnesses based on the symptoms that a person has. The same is true for migraines, Alzheimer’s disease, and Parkinson’s disease, all currently diagnosed by their symptoms alone.

Mental health professionals rely on the criteria specified in the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision (DSM-IV-TR), published by the American Psychiatric Association, to diagnose a specific mental illness. For each mental illness, the DSM-IV gives a general description of the disorder and a list of typical symptoms. Observing patients over a period of time, mental health professionals refer to the DSM-IV to confirm that the symptoms a patient exhibits match those of a specific mental illness or illnesses. There is a diagnosis code associated with each specific disorder. For example, the code for Post-Traumatic Stress Disorder (PTSD) is 309.81.