Global Assessment Of Functioning (GAF): Scale & Overview

Instructor: Chevette Alston

Dr. Alston has taught intro psychology, child psychology, and developmental psychology at 2-year and 4-year schools.

This lesson briefly describes the Global Assessment of Functioning, or GAF, and how it is used to rate a person's overall level of mental health during a diagnostic interview.

What Is a GAF?

GAF is an acronym for Global Assessment of Functioning. The GAF is a psychological rating scale that ranges from 0 to 100. Higher scores indicate greater levels of functioning. The most favorable mental health functioning is represented by scores that range from 91 to 100. Those with minor psychological problems are rated in the 71 to 90 range of functioning. Severe mental health concerns fall in the 21 to 30 range. Ratings that range from 1 to 10 are reserved for those who are persistently suicidal or people who are incapable of meeting minimal standards of personal care. A GAF rating is a standard part of all psychiatric/psychological diagnoses. The GAF score is often given on Axis V of the Diagnostic and Statistical Manual's multi-axial diagnostic system.


Axis V (Overall Level of Functioning)

Axis V is where a clinician gives his or her impression of the client's overall level of functioning. This level of functioning is measured by matching information about the client's overall level of functioning with descriptions on the GAF scale. Social history information is used to make this judgment and is obtained from the diagnostic interview with the client and from the results of psychological testing. Most people who need therapy for psychological problems will not be rated at the top of the GAF scale.

It is often useful to make a basis of comparison between the client's current GAF and his or her GAF at a time when he or she was functioning better. Clinicians often try to figure out what the highest GAF was within the past year because a therapy goal will be to restore the client's functioning to at least the highest level of functioning achieved within the last year. The GAF scale is summarized below and is for lesson purposes only.

The Global Assessment of Functioning Scale

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