An Axis I diagnosis is a clinical mental health evaluation of symptoms that are severe enough to cause a disruption in multiple areas of the patient's life. The therapist will use a series of tests and refer to the Diagnostic and Statistical Manual, Fourth Edition, Text Revision (DSM IV-TR) to assist in correctly determining the cause or causes of the symptoms that are disrupting the patient's life and develop a treatment plan that will best suit that patient. Each patient is unique and will respond differently to treatment, and if there is a dual diagnosis, treatment can become even more complicated.

A dual diagnosis is one term used to signify a diagnosis on both Axis I and Axis II. Common dual diagnoses include, but are not limited to, Depression and Oppositional Defiance Disorder, or Bipolar Disorder and Reactive Attachment Disorder. Dual diagnosis may also refer to a substance abuse addiction in addition to a behavioral disorder. There are four Axis levels in the DSM IV-TR. Axis II deals with the personality and relational aspects, Axis III the medical diagnostics, and Axis IV is for the Global Assessment of Functioning (GAF) score.

Axis I determines the treatment flow of the rest of the assessment. Some might argue that Axis III, the medical assessment, is the most important, and if an immediate threat to life is concerned, they would be right. However, for the purpose of diagnosis and treatment planning, the Axis I designation is the place to start. By getting to the root cause of a particular behavior, a positive effect for a medical outcome can be achieved. In the same way that a physician has to correctly diagnose was is causing the body to behave in an abnormal way, so the therapist has to draw on the tools of the mental health field, which include education, experience, and for timely diagnosis, the DSM IV-TR.

The body develops survival strategies to deal with issues that overwhelms the mind and can remain integrated into the psyche. Left untreated, these behaviors can cause major disruptions to not only the patient’s life, but to everyone the patient comes in contact with. Untreated psychological issues can affect the body in a myriad of ways. For instance, a persistent rash can be a physiological response to an external stressor. Chronic bed wetting may not just be a bladder dysfunction to be treated with Tofranil, but the result of an external stressor such as divorce, drug abuse or sexual trauma. Unless the entire body is treated, a return to normal functioning is unlikely if not impossible.