Mental disorders are diagnosed according to a manual published by the American Psychiatric Association called the Diagnostic and Statistical Manual of Mental Disorders.
A diagnosis under the fourth edition of this manual, which was often referred to as simply the DSM-IV, had five parts. Each part, called an axis, gave a different type of information about the diagnosis.
- Axis I provided information about clinical disorders. Any mental health conditions, other than personality disorders or mental retardation, would have been included here.
- Axis II provided information about personality disorders and mental retardation.
- Axis III provided information about any medical conditions that were present.
- Axis IV was used to describe psychosocial and environmental factors affecting the person.
- Axis V was a rating scale called the Global Assessment of Functioning; the GAF went from 0 to 100 and provided a way to summarize in a single number just how well the person was functioning overall.
When the fifth edition, the DSM-5, was compiled, it was determined that there was no scientific basis for dividing the disorders in this manner, so the multi-axial system was done away with. Instead, the new non-axial diagnosis combines the former Axes 1, II and III and include separate notations for the type of information which would have previously fallen into Axes IV and V.