Description

The Global Assessment Scale (TGAS), also known as the Global Assessment of Functioning Scale (GAF), is a clinical assessment instrument designed to provide a comprehensive evaluation of an individual’s overall functioning, particularly in cases involving mental disorders. The scale assesses the individual’s psychological condition together with the degree to which they maintain their daily activity and functionality.

The TGAS was developed by Spitzer et al. (1976) and was adapted into the Greek language by Madianos (1987). The scale is based on the concept that an individual’s overall functioning at a specific point in time can be positioned along a continuum ranging from mental health to mental illness.

Objective

The main objective of the TGAS is to evaluate the overall functional status of individuals experiencing psychological difficulties.

The scale aims to:

Assess Psychological Functioning, by identifying the impact of psychopathological conditions on the individual’s everyday life.

Evaluate Activity Level and Autonomy, by examining the extent to which individuals maintain their ability to function and participate in daily activities.

Combine Symptom Assessment and Functioning Evaluation, by simultaneously considering the presence of psychological symptoms and the preservation of individual activity.

Structure and Content

The TGAS is a global, single-score assessment scale that evaluates overall functioning through a continuum of psychological health and impairment.

The assessment considers:

Psychological Symptoms, referring to the presence and severity of mental health difficulties.

Social Functioning, referring to the individual’s ability to interact and maintain social relationships.

Daily Activity and Functionality, referring to the level of independence and engagement in everyday life.

The evaluation refers specifically to the individual’s functioning during the month preceding the assessment.

Scoring Method

The TGAS is divided into ten equal sections, with scores ranging from:

1 to 100.

The interpretation of scores is as follows:

80–100: Individuals without significant psychological or physical difficulties, who maintain social activity and strong interpersonal interaction.

31–70: Individuals experiencing psychological difficulties who may seek professional mental health support.

1–30: Individuals with severe impairment, often corresponding to those requiring psychiatric hospitalization.

Higher scores indicate better overall functioning, while lower scores indicate greater impairment.

Data Analysis and Use

The analysis of TGAS scores focuses on examining the relationship between psychological symptoms and functional capacity.

Possible statistical approaches include:

Correlation Analysis, examining associations between TGAS scores, autonomy, and activity level.

Clinical Comparison Analysis, comparing functioning levels between different psychiatric populations.

Predictive Analysis, evaluating the ability of TGAS scores to predict deterioration or improvement in clinical status.

Validity

The validity of the TGAS has been supported through correlations between total scores and the degree of autonomy and activity maintained by individuals.

A significant correlation was reported between TGAS scores and functional autonomy:

r = 0.65 (p = 0.01).

Additionally, a negative relationship was observed between the number of symptoms associated with schizophrenic psychosis and the level of functioning.

Using a cutoff value of 40, it was found that 84% of individuals with scores between 10 and 40 experienced deterioration of their condition, demonstrating the predictive ability of the scale.

Reliability

The reliability of the TGAS was evaluated through assessments conducted by two independent psychiatrists.

The reliability coefficient was:

0.74

indicating satisfactory agreement between evaluators.

The scale also demonstrated high reliability in repeated assessments, supporting its stability over time.

Applications

The Global Assessment Scale can be applied in:

Clinical psychiatry and mental health services.

Research examining psychiatric disorders and functional impairment.

Evaluation of treatment outcomes and changes in psychological functioning.

Assessment of relationships between symptoms, autonomy, quality of life, and daily functioning.

The TGAS provides a concise and clinically useful measure of overall functioning and the impact of mental health conditions on everyday life.

References

Madianos, M., Economou, M., Peppou, L. E., Kallergis, G., Rogakou, E., & Alevizopoulos, G. (2012). Measuring public attitudes to severe mental illness in Greece: Development of a new scale. The European Journal of Psychiatry, 26(1), 55–67.

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.

Κλεάνθους, Ε. (2019). Διερεύνηση της σχέσης ανάμεσα στις ανάγκες, την ποιότητα ζωής και την ολική λειτουργικότητα των ψυχικά πασχόντων στην Κύπρο. Διδακτορική διατριβή, Εθνικό και Καποδιστριακό Πανεπιστήμιο Αθηνών.