Greek McGill Pain Questionnaire: validation and utility in cancer patients.

In 1968, Melzack and Casey suggested that there are three major psychological dimensions of pain: sensory, affect, evaluative. These categories interact with one another to provide quantitative and qualitative information on the components of pain. In 1975, Melzack developed the McGill Pain Questionnaire, which is composed of four major parts and evaluates the qualities of pain. The aim of this study was to assess the applicability, reliability, and validity of the McGill Pain Questionnaire on a sample of Greek cancer patients receiving palliative treatment. It was administered to 114 cancer patients before the initiation of the palliative treatment, and then to 80 cancer patients during the treatment 7 days later. The results indicated that scale reliability was very good (0.95-0.97). During the pretreatment period, correlations between Present Rating Index (PRI), Present Pain Intensity (PPI), and Number of Words Chosen (NWC) ranged between 0.42 and 0.92. During the post-treatment time, the correlations ranged between 0.28 and 0.91. Only 21.8% of the words met a criterion of 30% for representativeness on the first administration of the questionnaire, and 9% met this criterion on the second. Validity was satisfactory (P < 0.005) according to "responsiveness to changes in time", as there was a statistical difference between the pretreatment and post-treatment time. Patients presented a desirable level of convergent construct validity (P < 0.05) concerning their performance status. Exploratory factor analysis was examined and two factors with eigenvalue over 1 were extracted, and they accounted for 95.2% of the variance. These results support the Greek-MPQ as a reliable and valid measure for evaluating the qualities of cancer pain in patients receiving palliative care.