Direct measurement of disability.

Schizophrenia is associated with substantial disability in everyday functioning. Environmental factors, such as disability compensation and opportunities, impact on the ability of people with the illness to perform real-world activities, particularly those that are vocational in nature. Measures of abilities to perform these functions have been developed that measure competence in social, everyday living, and vocational domains. These indices have measurement characteristics consistent with those of neuropsychological tests, indicating that they have the potential to be valid measures of the ability to perform in real-world functional situations. It is our belief that these measures will be widely employed in later research on functioning in schizophrenia, and many of these tests have the potential to be used in clinical settings.