Assessing Negative and Positive Mood States: the identification of a short form of the POMS scale in Italian oncology outpatients

In line with the interest of constructing brief questionnaires to be used in clinical settings, in this research a short form Italian version of the 65 item Profile of Mood States scale (POMS - McNair, 1971/1981, Italian version: Farn\ue8 et al., 1991) was derived for oncology patients, by analyzing the responses of 108 cancer patients. In study 1, by means of a Principal Component Factor Analysis, a 50 item two factor structure was obtained, denominated Negative (40 items) and Positive (10 item) Mood States (NPMS) scale. Both factors showed to be consistent internally and correlated with external variables. In study 2, in a latent trait perspective, an Item Response Theory analysis was applied. The previous factors were confirmed and reduced to 7 and 6 items respectively. The new 13 items scale was then denominated Negative and Positive Mood State Short Form (NPMS-SF)