Assessment of premorbid function in first-episode schizophrenia: modifications to the Premorbid Adjustment Scale.

Studies have found Cannon-Spoor's Premorbid Adjustment Scale (PAS) to be a useful measure of premorbid function and an effective predictor of outcome in patients with chronic schizophrenia. Despite its widespread use, the applicability and reliability of the scale for use with young patients who experience their first episode of schizophrenia have not been thoroughly examined. We review the studies that used the PAS to assess premorbid function in patients with either chronic or first-episode schizophrenia. Difficulties that have been encountered with the use of the PAS in first-episode patients are presented, and modifications that have been made to the scale by various research groups are described. Finally, we make recommendations to enhance the use of the PAS when evaluating patients who have experienced their first episode of schizophrenia.