Informed versus blind: the reliability of cross-sectional ratings of psychopathology

Fifty subjects at the New York facility of the National Institute of Mental Health Clinical Research Branch Collaborative Program on the Psychobiology of Depression were evaluated for cross-sectional psychopathology and functional impairment at the 2-year followup by two professional raters, one blind and one with extensive knowledge of the subject's psychiatric history and course of illness and treatment (the cohort rater). Ratings were made on the change version of the Schedule for Affective Disorders and Schizophrenia. Interrater reliability, as tested using the intraclass correlation coefficient, was quite good for most of the symptom ratings and fair on measures of functional impairment and social functioning. However, there was a consistent tendency for the blind rater to score higher levels on symptoms of depression and anxiety than the informed cohort rater. Reasons for disagreement in different symptom areas are discussed. Using only the informed rater provides a very adequate picture of severity and patterns of psychopathology on a cross-sectional basis.