Psychiatric services : a journal of the American Psychiatric Association
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Standard scales for measuring anxiety and depression did not distinguish between these two psychological constructs in a sample of 295 inpatients with major depressive disorder. Items from these scales were used to form new measures, based on the results of a factor analysis. ⋯ When the factorial procedure was repeated with a subsample of patients with only mild to moderate symptoms, there was no discrimination between depression and anxiety. This finding suggests that when measured in a sample with a restricted range of symptom severity, anxiety and depression have poor discriminant validity.