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Global Assessment of Functioning

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Purpose

A scale-based measurement reflecting the degree to which a person’s current symptoms affect their psychological, social, and occupational functioning on a range from 0 to 100. A higher score reflects higher functioning in everyday life based on scored criteria.

Link to Instrument

Instrument Details

Acronym GAF

Area of Assessment

Executive Functioning

Assessment Type

Observer

Administration Mode

Paper & Pencil

Cost

Free

Actual Cost

$0.00

Populations

Key Descriptions

  • The Global Assessment of Functioning (GAF) measures psychological, social, and occupational functioning through an assessment of how symptoms affect an individual’s daily life. GAF scores are based on client interviews, questionnaires, medical and legal records, and information from secondary informants. The higher the client scores on a scale of 0 to 100, the better the client is able to handle activities of daily living (ADLs).
  • Clinical judgment respecting only to psychological, social, and occupational functioning
  • 10 ranges describe varying symptom severity and functioning, with the scores reflecting overall level of functioning
  • Time period of assessment is reflected
  • 1 reflects most persistent and severe symptoms and functional impairment; 0 indicates inadequate information

Time to Administer

 minutes

Required Training

Training Course

Required Training Description

Level B qualification is recommended.
There is no consensus on required training. However, it is suggested that administrators receive formal training (Bates et al., 2002). Studies show that professionals such as nurses, social workers, psychologists, physical therapists, general practitioners, and psychiatrists have administered it in the past (Hall, 1995).

Age Ranges

Preschool Children

2 - 5

years

Child

6 - 12

years

Adolescent

13 - 17

years

Adult

18 - 64

years

Elderly Adult

+

years

Instrument Reviewers

Sinyoung Park, Megan Ramirez and Noppawan Tunsirimas

ICF Domain

Activity
Participation

Measurement Domain

Activities of Daily Living
Cognition
Emotion

Professional Association Recommendation

The American Psychiatric Association introduced the use of GAF in the DSM III-TR and continued to include it in the DSM IV and DSM IV-TR (1987, 1994, 2000).

Considerations

  • The assessment does not consider impairment due to physical or environment limitations.
  • The rating scale is subjective.
  • Limited instructions for scoring within 10-point intervals available.
  • Limited relationship to prognosis
  • It is not included in the current edition of Diagnostic and Statistical Manual of Mental Disorders (DSM, 2013).

Mental Health

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Test/Retest Reliability

Psychiatric disorders in inpatients: (Spitzer 1979)

  • Satisfactory test-retest reliability (ICC=0.69)

Interrater/Intrarater Reliability

Psychiatric disorders:(Jones et al., 1995)

  • Satisfactory intrarater reliability (ICC = .65)

Internal Consistency

Psychiatric disorders:(Söderberg et al., 2005)

Acceptable internal consistency (Cronbach’s alpha = 0.98), first-time patients at outpatient psychiatric clinics

Criterion Validity (Predictive/Concurrent)

Concurrent Validity

Schizophrenia: (Schwartz et al, 2007; n = 170 participants with schizophrenia diagnosis per DSM-IV; mean age = 39.2 (9.8) years)

  • Compared the participant’s GAF scores with their scores on the Functional Assessment Rating Scale (FARS; Ward & Dow, 1994)
  • The omnibus multiple regression model showed that the FARS score significantly predicted the GAF scores  (F4,165 =26.8, p < 0.001)

Construct Validity

Schizophrenia: (Schwartz et al., 2007; n = 170 participants with schizophrenia diagnosis per DSM-IV; mean age = 39.2 (9.8) years)

  • Compared the GAF scores with Functional Assessment Rating Scale (FARS; Ward & Dow, 1994) scores and found that clinicians rated psychotic symptoms, work and school related problems, and danger to others as affecting overall functioning for both scales and scores were correlated for these three variables.
  • Of the four variables — severity of psychotic symptoms, work-related problems, danger to others, danger to self —only the first three were significantly correlated to the client’s GAF scores.

Variables

Beta weights

t165

Correlation

severe psychotic symptoms

-2.6

-6.7

-0.55*

work and school related problems

-1.0

-3.2

-0.31*

danger to others

-1.6

-3.3

-0.40*

danger to self

-.44

-.82

-0.05

  • Results provide support for construct validity of the GAF scale for use with clients with schizophrenia.

Anxiety Disorder: (Schwartz & Prete-Brown, 2003; n = 33 participants with anxiety disorder per DSM-IV-R; mean age = 31.0 (10.6) years)

  • To evaluate the construct validity of GAF, the study compared the GAF scores with four variables of the Functional Assessment Rating Scale (FARS; Ward & Dow, 1994)--suicidality, homicidality, work and school related problems, and self-care deficits
  • Multiple regression results found overall statistically significant correlation (F5.27 =2.78, p < 0.05), which suggests that GAF is a valid screening scale for overall mental health severity among clients with anxiety disorder

Content Validity

Psychiatric disorders: (Roy-Byrne et al., 1996; n= 337 psychiatric inpatients) examined the content validity of the GAF scale by comparing the GAF scores with nurses’ rating of the Lehman’s Quality of Life Scale and found that the GAF is most strongly correlated with ratings of clinical symptoms

Face Validity

Not statistically assessed; however, several researches report that the GAF is the standard method of assessing mental health patient’s global functioning. Also, the GAF was previously the most widely utilized clinician rating psychiatric diagnostic scale used in conjunction with the DSM-IV (Schwartz & Del Prete-Brown, 2003).

Bibliography

Aas, I. M. (2010). Global Assessment of Functioning (GAF): Properties and frontier of current knowledge. Annals of General Psychiatry, 9, 20. https://doi.org/10.1186/1744-859X-9-20

 

Aas I. H. (2011). Guidelines for rating Global Assessment of Functioning (GAF). Annals of general psychiatry, 10, 2. https://doi.org/10.1186/1744-859X-10-2

 

American Psychiatric Association. (1987). Diagnostic and statistical manual of mental disorders (3rd ed., text rev.). Washington, DC: Publisher.

 

American Psychiatric Association. (1994). Diagnostic and statistical manual of mental disorders (4th ed.). Washington, DC: Publisher.

 

American Psychiatric Association. (2000). Diagnostic and statistical manual of mental disorders (4th ed., text rev.). https://doi.org/10.1176/appi.books.9780890423349

 

American Psychiatric Association. (2013). Assessment Measures. In Diagnostic and statistical manual of mental disorders (5th ed.). Washington, DC: Publisher.

 

Bates, L. W., Lyons, J. A., & Shaw, J. B. (2002). Effects of Brief Training on Application of the Global Assessment of Functioning Scale. Psychological Reports, 91(3), 999–1006. https://doi.org/10.2466/pr0.2002.91.3.999

 

Endicott, J., Spitzer, R. L., Fleiss, J. L., & Cohen, J. (1976). The Global Assessment Scale: A Procedure for Measuring Overall Severity of Psychiatric Disturbance. Archives of General Psychiatry, 33(6), 766–771. https://doi.org/10.1001/archpsyc.1976.01770060086012

Goldman, M., Dequardo, J. R., Tandon, R., Taylor, S. F., & Jibson, M. (1999). Symptom correlates of global measures of severity in schizophrenia. Comprehensive Psychiatry, 40(6), 458–461. https://doi.org/10.1016/S0010-440X(99)90090-1

Goldman, H. H., Skodol, A. E., & Lave, T. R. (1992). Revising axis V for DSM-IV: a review of measures of social functioning. The American Journal of Psychiatry, 149(9), 1148-1156. DOI: 10.1176/ajp.149.9.1148

Hall, R.C. (1995). Global assessment of functioning: A modified scale. Psychosomatics, 36(3), 267-275. https://doi.org/10.1016/S0033-3182(95)71666-8

 

Jones, S., Thornicroft, G., Coffey, M., & Dunn, G. (1995). A Brief Mental Health Outcome Scale: Reliability and Validity of the Global Assessment of Functioning (GAF). British Journal of Psychiatry, 166(5), 654-659. doi:10.1192/bjp.166.5.654

 

Pedersen, G., Urnes, Ø., Hummelen, B., Wilberg, T., & Kvarstein, E. H. (2018). Revised manual for the global assessment of functioning scale. European Psychiatry, 51, 16-19. DOI: 10.1016/j.eurpsy.2017.12.028

 

Roy-Byrne, P., Dagadakis, C., Unutzer, J., & Ries, R. (1996). Evidence for limited validity of the revised Global Assessment of Functioning Scale. Psychiatric Services, 47, 864-866.

 

Shaffer, D., Gould, M. S., Brasic, J., Ambrosini, P., Fisher, P., Bird, H., & Aluwahlia, S. (1983). A Children’s Global Assessment Scale (CGAS). Archives of General Psychiatry, 40(11), 1228–1231. https://doi.org/10.1001/archpsyc.1983.01790100074010

Schwartz, R. C. (2007). Concurrent Validity of the Global Assessment of Functioning Scale for Clients with Schizophrenia. Psychological Reports, 100(2), 571–574. https://doi.org/10.2466/pr0.100.2.571-574

Schwartz, R. C., & Del Prete-Brown, T. (2003). Construct Validity of the Global Assessment of Functioning Scale for Clients with Anxiety Disorder. Psychological Reports, 92(2), 548–550. https://doi.org/10.2466/pr0.2003.92.2.548

Söderberg, P., Tungström, S., & Armelius, B. A. (2005). Special Section on the GAF: Reliability of Global Assessment of Functioning Ratings Made by Clinical Psychiatric Staff. Psychiatric Services, 56(4), 434–438. https://doi.org/10.1176/appi.ps.56.4.434

Spitzer RL, Forman JBW: DSM-III field trials, II: initial experience with the multiaxial system. Am J Psychiatry 1979; 136: 818-820

Støre-Valen, J., Ryum, T., Pedersen, G. A. F., Pripp, A. H., Jose, P. E., & Karterud, S. (2015). Does a web-based feedback training program result in improved reliability in clinicians’ ratings of the Global Assessment of Functioning (GAF) Scale? Psychological Assessment, 27(3), 865–873. https://doi-org.ezproxy.library.wisc.edu/10.1037/pas0000086