Global Assessment Of Functioning (GAF): Scale, Lesson & Quiz

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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.

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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

Code Mental Health Functioning
100-91 Client has superior functioning in various life activities, can deal with daily problems and shows no symptoms.
90-81 Client has no or few symptoms, has good functioning in various life activities and is, overall, satisfied with his or her life.
80-71 Symptoms are generally temporary and common reactions to psychosocial stimuli, and the client shows only slight social, school or occupational functioning impairment.
70-61 Client shows either mild symptoms or difficulty in social, school or occupational function; however, he or she still has healthy relationships and functions fairly well.
60-51 Client has either moderate symptoms or difficulties functioning in social, school or occupational life.
50-41 Client has either serious symptoms, such as suicidal thoughts or addictive behavior, or a serious social, school or occupational functioning impairment.
40-31 Client exhibits either difficulty in reality testing or communication or difficulty in multiple activities, like work, judgment or mood stability.
30-21 Client shows either difficulty in judgment or communication or major difficulty functioning in several life activities, such as work, school or even waking in the morning. A client may also receive this score if his or her actions are affected by delusions or hallucinations.
20-11 Client is in danger of hurting him or herself or has an extreme communication impairment. A client may also receive this score if he or she cannot maintain basic personal hygiene.
10-1 Client is in constant danger of hurting him or herself or has attempted suicide. A client may also receive this score if he or she cannot maintain basic personal hygiene.
0 There is not enough information to diagnose this client's mental health functioning.

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