What aspect of functioning does the Global Assessment of Functioning (GAF) measure?

The Global Assessment of Functioning (GAF) is specifically designed to measure an individual's overall psychological, social, and occupational functioning on a continuum. It primarily focuses on the impact of mental health issues on a person's ability to function in daily life, particularly in those with psychiatric disorders. The GAF score helps clinicians and researchers gauge the severity of mental health symptoms and their effect on a person's overall functioning, offering insight into how well an individual is managing in various life domains.

While social engagement, levels of communication, and physical mobility may be relevant in understanding an individual's overall health and well-being, they do not encapsulate the broader spectrum of functional assessment that the GAF focuses on, especially in relation to mental health issues. The emphasis on psychiatric disorders is what makes option C the most appropriate response, as it aligns with the GAF's purpose within clinical practice and assessment.