Objective: The aim of this study was to develop a questionnaire for measuring depressed patients' knowledge of their disease.
Methods: 55 patients suffering from depressive episodes answered a 77-items questionnaire.
Results: Item analysis showed a discriminative power higher than 30 for 40 items, all of which applied to one factor. The items were arranged into two thematically similar 20 items forms. We added four additional items (discriminative power between 0.20 and 0.29) because future research may lead to different results concerning discriminative power. The questionnaires DEWIPA-A and DEWIPA-B consists of 24 items each. The average difficulty is equal for both DEWIPA forms and they both possess significant discriminative power.
Conclusions: Our results support the hypothesis that DEWIPA is a valid and reliable instrument to determine patients' knowledge of symptoms, causes and the psychopharmacological treatment of depression.